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📈 Part 1: Introducing My Momentum Strategy: levGTAA

⏱️ Reading time: approx. 15–25 minutes


Hello everyone,


Up until now, I’ve mostly been a quiet reader on getquin. Behind the scenes, however, I’ve been exploring the topic of momentum strategies for quite some time. Over the past few weeks and months, I’ve been conducting relatively intensive backtests on leveraged GTAA and SpyTips using AI (Claude Opus 4.8 and 5.5). My price data—and thus the backtest period—covers the years 1987 to 2026 (Bitcoin data starting in 2014). I’ve also been regularly @Epi .


Due to the length of this particular post, I’m splitting it into three parts:

- Part 1 (this post): my momentum strategy, levGTAA

- Part 2: a comparison of implementations—wikifolio vs. personal portfolio

- Part 3: levTipsRegime, my slightly modified SpyTips strategy


First off: Nearly all of the following tests were conducted using AI. This is not investment or financial advice, nor is it a recommendation to buy or sell securities or financial products. AI can make mistakes. Do your own research! :)


Likewise, much of the text below was pre-written by the AI chatbot I most recently used to run the backtests. However, I have thoroughly proofread, edited, and expanded upon the text. Let’s get started!


📐 MY APPROACH


Data source: Daily prices from 1987 to 2026. Calculations are based on investable returns (for ETFs starting from their inception; prior to that, older indices/funds, calibrated to the ETF). For leveraged products, financing costs, product costs, and spreads are included. Signals are always generated based on the closing price; trades are executed only afterward—so there’s no attempt to predict the future.


Initial finding: When you trade during the month makes a big difference. In the final model, the return ranges from 24.2% to 30.4% per annum, depending on the trading day; the last day of the month ranks among the best days at 30.0% (3rd out of 21), while the average across all days is 28.1%. Anyone who tests only the last day of the month therefore overestimates the expected return by about 2 percentage points. That’s why I evaluate each variant as an average across all 21 possible trading days of a month. Although trading in the wikifolio still takes place at the turn of the month, the parameters were designed for the average of all days, not for the “lucky day.”


The Robustness Score

I tested a large number of asset baskets, parameter variations, and additional methods (e.g., dynamic parameters). To compare the variations fairly, I developed a robustness score. Of course, this does not guarantee future performance. However, the score assesses how stable past performance was and how large a portion of it was due to chance. It consists of three components:


1. MC5 (Monte Carlo, parameter robustness): Daily returns are randomly reassembled into monthly blocks. This generates 800 alternative scenarios that could have occurred. The Sortino ratio is measured in the pessimistic case (5th percentile). In the basket search, this was calculated not only for the selected parameters but also in parallel for several parameter variants (for the momentum strategy, e.g., SMA 100, 120, … 200 instead of 150; for other strategy types, a different ranking metric was also used), and the results were then averaged. If performance remains stable when the parameters are adjusted, the score increases.

2. Minimax5 (worst phase): The time period is divided into 5 equally long segments. The Sortino ratio is measured in the worst segment, specifically for the worst parameter variant (Worst of Worst). A strategy that performs well in only one of the five phases fails this test.

3. Risk: the maximum drawdown (score version “z-dd”) or the total Sortino (score version “z-Sor”).


Each component is compared against a large benchmark pool of all tested basket/strategy combinations (robust z-value based on median and standard deviation), and then the variants are averaged. z = 0 means “as good as the typical combination”; the higher the value, the more robust the strategy.


In addition, I examined: Minimax3 (the same with 3 segments), Worst Year, the longest drawdown period, separate halves and market phases, turnover, and the probability of experiencing a drawdown of more than 50% or 75% within 10 years (P50/P75; simulated from 2,000 10-year sequences randomly assembled from real annual blocks).


Overfitting Tests (brief explanation)

- PBO / CSCV (Bailey & López de Prado): The historical data is divided into 10 blocks and split into all possible training and test halves. The metric measures how often the top-performing strategy from the training half falls below the median in the test half. For context, based on my control simulation: By pure chance, the average value is 42%, but it varies widely (10–90%); only a very significant advantage (approx. +20% p.a.) brings the average down to 16%. PBO therefore reliably detects only large differences and is thus just one of several tests.

- Walk-forward: Select parameters in one period; test them in the next.

- Halving test: Does the parameter landscape look similar in both halves of the history?

- Paired bootstrap: What is the probability that variant B is truly better than A and not just by chance?

- Rolling 10-year windows: In what percentage of all windows does a variant win?

- Minimax regret: Which choice does the model regret the least across all scenarios?

- Stress Scenarios: Bitcoin calculated with a CAGR of 0% per year based on available price data from 2014; bonds calculated without the overweight scenario of falling interest rates during the test period; higher costs

- Plateau instead of peak: Whenever possible, choose the midpoint of a stable parameter range; never the single peak (the best value due to the risk of overfitting).


1️⃣ levGTAA (leveraged GTAA)—essentially a variation of 3xGTAA (in consultation with @Epi )


The basket: Nasdaq 100 (3x), Bitcoin (1x), gold (3x), and bonds (5x TLT, long-term U.S. Treasuries, or alternatively, for liquidity reasons, 3x IEF with 7–10-year maturities).


Trading takes place once a month. This is nothing new compared to 3xGTAA. The signals are always calculated based on the unleveraged prices in USD; the leverage is applied only during execution.


What is new or different, however, is the following:

A brief note up front: The parameters discussed below are not set in stone for all time, and I would logically adjust them in the future based on new, important insights.


▸ A range of SMA values instead of a single value: There is no clear-cut optimum for the best SMA, but rather a broad plateau, and it is nearly impossible to predict which specific length is the best. A halving test using the final rule clearly demonstrates this: The best length for 1987–2006 (SMA180) ranked only 15th out of 21 for 2007–2026, where SMA210 came out on top. Across all individual lengths from 100 to 300 days (in increments of 10), the Sortino ratio ranges between 0.99 and 1.06. That’s why I don’t commit to a single value, but rather evaluate a range of SMA values, so to speak. The equally weighted range of SMA values (Sortino 1.05) is close to the optimal value without needing to know it in advance. One result of this is that the signal is less of an “all-or-nothing” principle. For example, if 70% of the SMA lengths indicate “trend intact,” 70% of the position is built up.

As the short-term SMA value (SMAx/SMA range), I use a slower value for x instead of the daily price—similar to Epi’s SMA10/150—though my specific model currently considers SMA30/SMA range to be the best solution. The daily price performs significantly worse, presumably due to more false signals: With the daily price, the return would be only 25.3% p.a. and the Sortino ratio 0.98 instead of 28.1% and 1.05, and the SMA30 outperformed the daily price as x in 99% of all 10-year windows (i.e., the SMA30 and @Epi its SMA10 outperformed, so to speak, SMA1).


▸ Two momentum rankings, each using half the capital: a fast ranking (1/3/6/9 months) and a slow one (3/6/12 months). The fast one detects reversals earlier; the slow one is more stable. It was nearly impossible to predict which ranking would be best (PBO across 11 tested rankings ranged from 42% to 71% depending on the scenario—essentially within the range of chance), so we use both instead of choosing one. The period during which momentum parameter ranges performed significantly better without the 1-month value was the dot-com crash. The 1-month strategy sometimes produced short-lived rebounds and thus false signals in aggressive assets like the Nasdaq 100 or emerging markets, which proved costly in the early 2000s. In a bull run like the one from 2010 to 2026, however, the 1/3/6/9 strategy—excluding BTC—was clearly superior. Among the predefined rankings, the mixed strategy had the best “worst trading day,” the second-lowest regret compared to the alternatives, and 11% fewer portfolio rebalancings than the fast ranking alone. With Bitcoin, the combination outperformed the fast ranking alone in 76% of the 10-year windows; without Bitcoin, the two are neck and neck (Sortino 0.826 vs. 0.827)—so the mix doesn’t hurt even without BTC. To be honest: In the backtest, the slow ranking alone actually came out ahead WITH Bitcoin (29.0% p.a., Sortino 1.07). However, this lead came almost entirely from the years 2022–2026 (especially BTC in 2024/25).


▸ Top 2 with 40/60 – The asset with the strongest momentum (1st place) receives 40%, and 2nd place receives 60%. It sounds counterintuitive, but the backtests support this (4-asset portfolio, 1987–2026):

- 40/60: 28.1% p.a. | maxDD −62% | Sortino 1.05 | P50 31%

- 50/50: 28.1% p.a. | maxDD −70% | Sortino 1.03 | P50 34%

- 66/33 (No. 1 overweighted): 26.9% p.a. | maxDD −83% | Sortino 0.96 | P50 48%

With the same return, overweighting the No. 2 position significantly reduces the risk of a sharp decline. One possible explanation: By that point, the momentum of the frontrunner has often already run out of steam. The 33/66 allocation is practically on par with 40/60 (Sortino 1.05), but involves more portfolio turnover (435% vs. 385% per year). Which allocation leads depends on the time period: From 1987 to 2006, 33/66 was ahead; from 2007 to 2026, 50/50 was even slightly ahead (Sortino 1.39 vs. 1.38). The 40/60 allocation falls in between and is chosen as a pragmatic solution: Across all stress scenarios, it never lagged behind the best allocation by more than 0.013 Sortino over the entire period. If only one asset in the basket has positive momentum and SMA, it receives 50%; the rest remains in cash.


▸ Vola-Cap 55% (a new methodology): Once a month, when selecting the Top 2, the volatility of the newly selected Top 2 portfolio (including leverage) is measured retrospectively over the last 2, 3, and 4 months. If the annualized volatility exceeds 55%, the position is proportionally reduced and the remainder is converted to cash. In other words: For each of the three time periods, the factor 55% / volatility (up to a maximum of 100%) is calculated, and the average of the three factors is invested. Example: The top 2 most recently had 80% volatility → only 55/80 ≈ 69% is invested instead of 100%. Without a volatility cap, the result was worse with an 89–94% probability according to paired bootstrap analysis (Sortino 1.02 instead of 1.05, P50 34% instead of 31%). There is hardly any difference between the volatility cap values of 50% and 60%: 50% was slightly ahead (Sortino 1.056 vs. 1.050), 60% lagged slightly behind (1.042), mainly because a 60% Volacap increases the maxDD compared to 55%, but does not provide a CAGR advantage. I therefore chose 55% as the midpoint of this stable range.


🧺 Selecting the Asset Basket


The final idea after all the backtests: When using only the Top 2, each asset should have its own role—ideally one asset per asset class, two offensive and two defensive.


A look at the correlations of monthly returns (unleveraged, 2015–2026) explains a lot: The stock markets tend to move in tandem (QQQ–EM 0.65, QQQ–EuroStoxx 50 0.66, EM–EuroStoxx 50 0.74; very similar since 1994). Bitcoin, on the other hand, is only weakly correlated with stocks (QQQ 0.31, EM 0.15), while gold and long-term bonds show little correlation with the other assets (Gold–QQQ 0.08, TLT–QQQ 0.23). A second equity asset therefore provides little real diversification, whereas Bitcoin, gold, and bonds do.


(Data format: CAGR | maxDD | Sortino | z-dd | z-Sor | P50 = probability of a >50% drawdown in 10 years)


First off—why not just include more assets? Comparison starting in 1987 (assets for which price data was not available prior to 1987 were simply added to the portfolio starting from the earliest available date):

- 4-asset portfolio (QQQ/BTC/Gold/TLT): 28.1% | −62% | 1.05 | 1.93 | 2.60 | 31%

- 7-asset portfolio (+ EM, EuroStoxx 50, WTI): 22.3% | −80% | 0.84 | 0.70 | 1.56 | 50%

- Group 9 (plus S&P 500, silver): 16.3% | −90% | 0.66 | −0.18 | 0.69 | 65%

→ More assets clearly perform worse here: The more similar assets compete for the top two spots, the less effectively assets can leverage their momentum, and the more often two related stock or commodity assets are likely to be in the lead at the same time, causing the decorrelation to be lost.


Step 1 – The Core: Stocks + Gold + Bonds

Do I even need bonds? Test: QQQ/BTC/Gold without bonds vs. with TLT, starting in 1987:

- without bonds: 22.3% | −61% | 0.87 | 1.22 | 1.61 | 17% | longest drawdown period 114
months (!)

- with 5x TLT: 28.1% | −62% | 1.05 | 1.93 | 2.60 | 31% | longest drawdown period 47 months

→ Add bonds to the portfolio: significantly higher returns, better Sortino and robustness scores, and drawdown periods are more than halved because bonds often rise during deflationary crashes like those in 2000–02, 2008, or 2020. The trade-off: The 5x leverage on bonds increases the risk of a deep drawdown (P50 31% instead of 17%). A possible solution: 3xTLT. However, it is not currently tradable in a practical way. More on this below.


Step 2 – The Fourth Asset Excluding Bitcoin: EM, EuroStoxx 50, or Oil? (from 1987 onward)

Regarding the data: EM is included in my analysis only starting in 1994, EuroStoxx 50 starting in 1990, and oil starting in 1987. Prior to that, the respective basket consists effectively only of the core trio.

- QQQ/Gold/TLT trio: 20.5% | −62% | 0.83 | 1.51 | 1.85 | 32%

- 3-component + EM: 24.7% | −62% | 0.91 | 1.68 | 2.14 | 36%

- 3-stock + EuroStoxx 50: 21.6% | −62% | 0.84 | 1.55 | 1.91 | 32%

- 3-Year+ EM and EuroStoxx 50: 25.0% | −62% | 0.91 | 1.67 | 2.14 | 36% (turnover 508% instead of 444% per year with EM alone)

- 3-year+ Oil (WTI 2x): 19.0% | −80% | 0.76 | 0.61 | 1.35 | 41% (longest drawdown period: 10 years)

Important note on maxDD: For all portfolios except WTI, the −62% stems from the crash of 1989–90, i.e., before EM or BTC data were available. Based on maxDD, these baskets cannot be distinguished from one another starting in 1987; however, they can be distinguished using P50, Sortino, and z-scores.

→ EM clearly outperforms the EuroStoxx 50. Together, they add practically nothing compared to EM alone—just more portfolio rebalancing—which makes sense given the 0.74 correlation between the two. EM delivers returns but also carries slightly more tail risk (P50 of 36% instead of 32%). The EuroStoxx 50 is eliminated. WTI significantly hurt the model on balance through 2015, costing total returns and pushing the maxDD to −80%, so it’s also out. Oil only looked good starting in 2015, mainly due to 2021 and 2026.


Step 3 – The actual portfolio decision: BTC, EM, or both? (Fair comparison starting in October 2015; short backtest period!)

My BTC data begins in 2014 (fully signal-capable starting in October 2015). That’s why the comparison starts in October 2015. To ensure BTC doesn’t win solely because of its exceptional rally, I technically stripped it of its entire return in one variant (0% CAGR over the period) while retaining its actual volatility. (-> Overfitting stress test).

(Data format: CAGR | maxDD | Sortino | P50; the z-scores are not comparable to the others in this short window)

- QQQ/Gold/TLT trio: 18.6% | −44% | 0.75 | 11%

- 3-stock portfolio + EM: 27.8% | −47% | 0.96 | 16%

- 3-stock portfolio + BTC with 0% CAGR: 30.1% | −50% | 1.07 | 24%

- 3-Year + BTC with 0% CAGR + EM (5 assets): 25.2% | −64% | 0.93 | 50%

- with actual BTC CAGR: 3-year + BTC 47.9% | −48% | 1.49 | 7% · 3-year + BTC + EM 43.5% | −58% | 1.37 | 16%

→ Particularly revealing: Even Bitcoin, which generated no returns, outperformed EM as the fourth asset in the past, delivering higher returns and a better Sortino ratio—albeit with a slightly higher drawdown risk (P50 24% vs. 16%). Apparently, momentum benefits from BTC’s strong trend phases, and BTC is less correlated with stocks (correlation with QQQ 0.31, vs. 0.65 for EM). Adding EM to BTC results in worse performance across all metrics, both with a real BTC CAGR and with a “BTC 0% CAGR”: Presumably, the strategy—with two equity assets in the portfolio and 3x leverage—is hit twice as hard during crises (5-asset portfolio with EM and BTC: maxDD with “BTC 0%” −64% from late 2017 to March 2020; with actual BTC, −58%).

To be honest: 11 years is not a long time. Logically, the differences in this short timeframe are therefore not statistically significant.


Interim conclusion—QQQ/BTC/Gold/TLT. EM as an addition is the only component I’m still considering, but the data tends to argue against it given the short backtest period.


Also eliminated (as already noted in the latest GTAA Workshop reports @Epi ): Currency pairs such as USD/EUR and EUR/USD have been eliminated due to a lack of stable momentum trends. Likewise, −TLT (short bonds): If interest rates do not continue to rise but instead stagnate, −TLT will likely lose value. -TLT tends to have asymmetrically negative volatility and is therefore unfavorable for momentum trends (which is typical for short indices).


Step 4 – The Bond in Practice: 5x TLT or 3x IEF or 1x TLT?

The product $TLT5 (+0,71%) has exorbitant costs (TCO over 7% per year). That’s why I compared the options directly (starting in 1992, since my data on medium-term bonds doesn’t begin until late 1991; all paired with BTC): (Data format: CAGR | maxDD | Sortino | P50)

- 5x TLT with low product costs: 33.0% | −48% | 1.20 | P50 15%

- 5x TLT with the actual 7% TCO: 31.1% | −48% | 1.15 | P50 17%

- 3x TLT: 31.2% | −44% | 1.20 | P50 7%

- 3x IEF (7–10-year term, only 0.3% TCO according to gq): 30.6% | −44% | 1.18 | P50 5%

- 1x TLT: 28.4% | −43% | 1.12 | P50 5%

→ When factoring in actual costs, 5x TLT offers virtually no advantage over 3x IEF but carries higher tail risk (P50). 3x TLT is slightly better than IEF but, unfortunately, is not currently tradable. That’s why I’m implementing 3x IEF (7–10y) for now. Important: All other backtests in this post use 5x TLT and low 5x TLT product costs.


Step 5 – Top 2 or Top 3? (from 1987 onward, same rule; Top 2 weighted 40/60, Top 3 equally weighted at 33/33/33)

(Data format: CAGR | maxDD | Sortino | P50)

- QQQ/BTC/Gold/TLT: Top 2 28.1% | −62% | 1.05 | 31% · Top 3 22.6% | −54% | 0.99 | 13%

- QQQ/EM/Gold/TLT: Top 2 24.7% | −62% | 0.91 | 36% · Top 3 19.5% | −54% | 0.81 | 21%

- QQQ/Gold/TLT/WTI: Top 2 19.0% | −80% | 0.76 | 41% · Top 3 15.1% | −66% | 0.68 | 23%

- QQQ/EM/Gold/TLT/WTI: Top 2 19.0% | −80% | 0.75 | 46% · Top 3 17.2% | −66% | 0.72 | 28%

- QQQ/EM/BTC/Gold/TLT/WTI: Top 2 22.6% | −80% | 0.86 | 48% · Top 3 21.9% | −66% | 0.87 | 27%

- QQQ/EU50/EM/Gold/TLT/WTI: Top 2 17.8% | −80% | 0.72 | 49% · Top 3 18.4% | −67% | 0.75 | 29%

→ The Top 3 strategy reduces the drawdown risk (maxDD and P50) in all portfolios. However, in 4-asset portfolios, it significantly reduces returns and Sortino, presumably because 3 out of 4 assets are held and the selection process barely filters anything. For 5- and 6-asset portfolios, the “Top 3” strategy is roughly on par in terms of Sortino (−0.03 to +0.03), but clearly ahead in terms of drawdown risk (maxDD −66/−67% instead of −80%, P50 27–29% instead of 46–49%). Rule of thumb: The larger the basket, the more likely “Top 3” is the better choice. For my 4-asset basket, I’m therefore sticking with “Top 2.”


Additional stress tests for the 4-asset basket starting in 1987: BTC 0% CAGR 23.6% p.a. | maxDD −62% | Sortino 0.92; bonds calculated without the overweight scenario of falling interest rates during the test period: 23.7% | −71% | 0.92; entirely without BTC (core 3-asset basket consisting of QQQ, gold, TLT) 20.5% | −62% | 0.83. While the strategy does lose significantly in this case, it is not dependent on a single stroke of luck.


📊 OVERALL


Backtest 1987–2026 for 3xQQQ, 1xBTC (starting in 2015), 3xGold, and 5xTLT:

- Average across all 21 possible trading days: 28.1% p.a. | maxDD −62% | Sortino 1.05 | z31 1.93 | z4 2.60 | P50 31% | P75 1.3%

- Only on the actual signal day (last day of the month): 30.0% | −70% | 1.08 | 1.88 | 2.82 | P50 34% | P75 3.0%

- Since 1992 (following the crash of 1989–90): 33.0% | −48% | 1.20 | P50 15%; with the implemented 3x IEF instead of 5x TLT: 30.6% | −44% | 1.18 | P50 5%


The probability of being down more than 50% at least once within 10 years (P50) was thus around 30–35% starting in 1987, and the probability of a maxDD exceeding 75% within 10 years was around 1–3%. Leverage also means deep troughs. My method aims to mitigate this primarily through the 55% volatility cap, the 40/60 weighting, and—above all—the portfolio selection, which includes only one asset per asset class; however, it cannot be prevented with 100% certainty.


⚖️ levGTAA vs. 3xGTAA – (even though I personally don’t view the two variants as competitors, but rather as two valid, equally valid options/variants)


In a direct comparison to 3xGTAA, levGTAA is, on the one hand, more complex to implement (SMA range instead of a single SMA value, 55% volatility cap, two momentum rankings), but on the other hand, it is leaner (4 assets in the basket instead of 6, as in @Epi currently, with the addition of WTI and EU50; top 2 instead of top 3). Overall, of course, both of our models can easily change at any time in light of new, promising insights and may even converge.


My assessment: @Epi The basket with the additional EU50 and WTI offers more variability and a wider selection of assets in case the trend consistency or momentum of QQQ and BTC becomes more unstable or if those two assets fall by the wayside over the decades. That is the disadvantage of my 4-asset basket and, at the same time, the strength of its asset basket. On the other hand, @Epi 's basket has other weaknesses: back-and-forth movement or inefficiency between the two equity assets, QQQ and EU50 (correlation 0.66), the drawdown risk of WTI, and the risk that WTI will no longer perform in the future the way it has since 2015. Both systems therefore have their respective advantages and disadvantages—and one must @Epi give 3xGTAA credit for the fact that its live track record on wikifolio to date provides thoroughly valid arguments for the validity of its model.


The most important insight for me: All of the optimizations mentioned above are fine-tuning. Much more important is the following consideration:

1. The greatest "optimization" of performance and robustness metrics is most likely to result from diversification across strategies—that is, combining, for example, B&H investments with systematic trend-following strategies and other methods that theoretically exist. In my opinion, this offers the best chance of improving the metrics and opportunities of one’s overall portfolio. Incidentally, levGTAA and levTipsRegime (Part 3) have a monthly correlation of approximately 0.5.

2. Second in importance, but far less relevant, is, in my opinion, the selection of the asset basket: Using exactly the same parameter rules, the tested baskets yield a CAGR ranging from about 16% to 29% per year (Sortino ratio 0.66 to 1.05). The goal should be to position oneself in the middle range or the top third. However, the optimal asset basket in the future is, of course, by no means predictable.

3. Parameter adjustments and other nuances are significantly less important: SMA length (Sortino 0.99–1.06), volatility cap (1.02–1.06), weighting 33/66 to 50/50 (1.03–1.05), top 2 vs. top 3 in a 4-asset portfolio (0.99–1.05; which is more a question of return versus drawdown depth than of quality).


So I’ve decided to implement both strategies as wikifolios.

Here are the two links:


levGTAA: https://www.wikifolio.com/de/de/w/wfxlevgtaa


levTipsRegime: https://www.wikifolio.com/de/de/w/wfxtipsreg


The next (much shorter) post (Part 2) will focus on a comparison of implementation: wikifolio vs. private portfolio. I’ll then introduce levTipsRegime in Part 3.


If I’ve forgotten anything or there’s a mistake somewhere, feel free to leave a short comment, and I’ll update the post.


Do you have any questions, criticism, comments, or requests?


Best regards, your flyingSquirrel


(or Sineqz, squirrel, flying squirrel, or whatever you want to call me)


⚠️ Important:

This is not investment or financial advice, nor is it tax advice. This is my personal approach and always my personal opinion. I created and evaluated the backtests with the help of AI, and AI can make mistakes. Backtests reflect past performance and are no guarantee of future results. Leveraged products can incur very high losses in a short period of time; the drawdowns mentioned above—and even higher ones, up to total loss—are a real possibility. Everyone should assess for themselves whether this approach is suitable for their own situation.


#gtaa
#momentum
#momentumstrategie
$QQQ3 (-6,87%)
$3LGO (+1,43%)
$BTC (+0,07%)

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30 Commenti

immagine del profilo
A Squirrel Flying Out of the Rabbit Hole!

Great post! 👌

Feel free to add it to #Bestof
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immagine del profilo
@Epi Thank you! I'm honored.
GTAA backtests are really a rabbit hole! 🫡😅
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immagine del profilo
@Epi You can pretty much forget about the "Best Of" tab
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immagine del profilo
Cool, thanks for the insights
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immagine del profilo
@DonkeyInvestor You're very welcome! Thanks for the coins, dear Donkey. :)
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immagine del profilo
I hope I didn't miss it—how were you able to backtest over such a long period of time?
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immagine del profilo
@valentin28 This is probably more information than you want to know, but I thought I'd go into detail here: :)

The basic principle is this: For the period before an ETF’s launch, you take the underlying index or an older fund and simulate it over the entire period leading up to the launch of the ETFs that are tradable today, using parameters that are as realistic as possible. This means: For indices, futures, and spot prices, a fixed annual premium or discount is added (e.g., for dividends, costs, or roll costs for commodities).

The AI then reconstructs the leveraged products day by day based on these parameters:

- Leverage × daily return, recalculated daily as with real leveraged ETPs (so path dependence is automatically included in the simulation)
- minus financing costs for the borrowed portion: short-term U.S. interest rate + 0.75% p.a. (1.75% p.a. for commodities such as gold)
- minus 0.75% p.a. product costs
- minus 0.2% trading costs on each rebalanced amount.

Uninvested funds are held in cash and earn interest at the short-term U.S. interest rate. The signals are calculated based on the unleveraged prices.

PRICE DATA FOR levGTAA

Nasdaq 100
- ^NDX (data since October 1985): the Nasdaq 100 Index.
- QQQ (since March 10, 1999): Invesco QQQ Trust, an ETF tracking the Nasdaq 100.

Long-Term U.S. Treasury Bonds
- VUSTX (since May 19, 1986): Vanguard Long-Term Treasury Fund, a traditional U.S. mutual fund investing in long-term U.S. Treasury bonds
- TLT (since July 22, 2002): iShares 20+ Year Treasury Bond ETF.

Gold
- LBMA Gold Price (data since April 1, 1968): the London benchmark price for gold.
- GC=F (since 2000): the continuous price series for gold futures on the U.S. COMEX futures exchange, available on Yahoo.
- GLD (since November 18, 2004): SPDR Gold Shares; according to its provider, State Street, the first physically backed ETF listed in the U.S.; the LBMA afternoon price serves as the benchmark.

Bitcoin
- BTC-USD (data starting September 17, 2014): Bitcoin price in U.S. dollars, unleveraged.

Interest Rates
- ^IRX: Cboe’s “13-Week Treasury Bill” index, i.e., the yield on 13-week (approx. 3-month) U.S. Treasury bills. It determines the interest rate on cash and the financing costs of leveraged products.

Additionally, for the basket tests
- Emerging Markets: VEIEX (since May 4, 1994), Vanguard Emerging Markets Stock Index Fund; starting in 2003, EEM, iShares MSCI Emerging Markets ETF.
- EuroStoxx 50: VEURX (since June 18, 1990), Vanguard European Stock Index Fund; from October 2002, FEZ, SPDR EURO STOXX 50 ETF.
- Oil: WTI spot price from FRED (since January 2, 1986); starting in 2000, CL=F, the WTI futures contract on the New York Mercantile Exchange (NYMEX); starting April 10, 2006, USO.

SOURCES:
- Yahoo Finance: This is the source of most of the price data for the indices listed above.
- FRED (Federal Reserve Economic Data): a free database from the Federal Reserve Bank of St. Louis. The WTI spot price (original source: U.S. Energy Information Administration) and the euro-dollar exchange rate come from there.
- Gold before 2000: historical series of the LBMA gold price.

The data begins in 1985/86. However, the first year serves as a lead-in period because the signals require up to 12 months of momentum and an SMA lead-in of up to 225 days. For this reason, the backtest does not begin until August 1987. Assets with later data start dates are included in the calculation only later (e.g., Bitcoin starting in 2015, EU50 starting in 1991); prior to that, the basket consists only of the remaining assets.

Limitation: In particular, prior to the respective ETF launch, these are simulated approximations and, taken as a whole, do not represent actual prices of the leveraged products available today.
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@flyingsquirrel Great, thanks. I've actually built a momentum agent too, but with individual stocks. The data is much harder to come by there, at least in my experience.

I'll be following your wiki 👍
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How does your four-stock portfolio actually perform when tracking the S&P 500 instead of the Nasdaq 100? That would probably have been the more obvious choice in 1987.
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@Yoshika I took a look: Same levGTAA rule, 1987–2026, averaged over all 21 trading days; Nasdaq 100 and S&P 500 each 3x, gold 3x, TLT 5x, BTC 1x (starting in 2015).

(CAGR | maxDD | Sortino | z-dd | z-Sor | P50 | P75)
• QQQ/BTC/Gold/TLT: 28.1% | −62% | 1.05 | 1.93 | 2.60 | 31% | 1.3%
• S&P 500/BTC/Gold/TLT: 23.2% | −56% | 0.94 | 1.90 | 2.24 | 22% | 0.4%
Excluding BTC for comparison, 1987–2026 (defensive 3-asset basket consisting of QQQ or S&P 500 + Gold + TLT): QQQ basket CAGR 20.5% | maxDD 62% | Sortino 0.83 vs. S&P basket 16.1% | 56% | 0.70

→ The QQQ basket has historically delivered nearly 5 percentage points more return per year and a better Sortino ratio. It outperformed in nearly 80% of all 10-year windows, even without BTC in the basket. According to paired bootstrapping, the S&P basket has only a 6% probability of outperforming and a 12% probability of having a better Sortino ratio.
→ The S&P 500 performed better in terms of drawdown risk: a lower maxDD and a P50 of 22% instead of 31%. The S&P basket performed better only from 2000 to 2009 (15.3% vs. 13.6% p.a.) because the Nasdaq 100 fell further after the dot-com bubble.
→ The two portfolios correlate at 0.92 on a monthly basis, meaning they perform relatively similarly overall, which makes sense given that only one asset was replaced and the two are quite similar.
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@flyingsquirrel
As a robustness test, I think it would be interesting to try a basket that could have been defined using rules as early as 1987.
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@Yoshika I agree in theory. But that would require at least 15–20 years of price data prior to 1987. On the other hand, the current backtest starting in 1987 already includes quite a few crisis periods as stress tests, and I’ve tried to use robustness methods to reduce the probability of overfitting and the probability that the backtest results turned out this way simply because they were biased by the specific market conditions from 1987 to 2026. Of course, a certain amount of risk remains; no one can predict the future. However, I tend to be rather skeptical as to whether a backtest prior to 1987—with a very narrow range of assets for the portfolio due to a lack of price data—truly provides such significant added value.
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@flyingsquirrel
I think you can do this without a long introduction. If you just followed the simple rule of choosing the established benchmark index for each asset class, you probably would have ended up with the S&P basket. The 16% figure excluding BTC would then at least be the more interesting benchmark. Still, nice post.
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@flyingsquirrel
I'm going to take a closer look at the SMA range—instead of a fixed value—and volatility control for my own strategy. Thanks for the suggestions.
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@Yoshika Thanks for now. You’re basically right—choosing the S&P 500 would certainly be the more established method. My reasoning behind preferring QQQ over the S&P is that it’s a more homogeneous index with a higher proportion of sectors and stocks that are correlated or move in tandem, which results in more stable trends. That’s also why we use only U.S. stocks and not a global stock index, which would be even broader. Another example here is the China issue in emerging markets (EM), which @Epi has often mentioned, since China somewhat distorts the momentum stability of EM. Overall, I’d say you can’t make a 100% case for either the QQQ or the S&P 500. 🤔
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@flyingsquirrel
I agree; there are arguments for both sides. Thanks for the discussion.
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@Yoshika Thanks to you, too, for the conversation. Have a great weekend!
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@flyingsquirrel
Thanks, you too! My weekend model recommends maximum exposure. 🧑🏻‍🩰🧑🏻‍🩰🥂
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@Yoshika Thanks! Great attitude!😂🫡
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Cool, you’re definitely going on my watchlist.
Wasn’t 3xGTAA risky/volatile enough for you? xD
With two highly leveraged assets that are rebalanced once a month, there’s definitely a significant risk of drawdown.
Maybe that wasn’t the case in the past because there was always another asset with more momentum, but who knows if those correlations will hold up in the future.
What will you do if 3xQQQ and 5TLT take off and the U.S. debt crisis gets serious next month?
Have you looked at the timing of the 2000 crash or the COVID crisis? In my backtests, a strategy like that was more about luck than an edge.
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@SemiGrowth
With MATT, you also put together the portfolio based on historical results and then optimized the parameters. How do you personally distinguish between luck and an edge?
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@Yoshika That's not what I mean. levGTAA probably has an edge. But the question is just how high the risk is. Let's say there's a coin toss. You either win 1 million or lose 900K, but you can only toss the coin once. Would you do it? You have an edge, but you can’t play it out statistically because a single negative event could wipe you out. With Matt, the risk is significantly lower, and trades are executed every 14 days.
Of course, this results in a lower return, but it significantly reduces tail risks.
In my opinion, lecGTAA has too high tail risks, but maybe you’ll get lucky.
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@SemiGrowth
But in the case of a true overnight Black Swan event, no time interval matters—whether it’s 14 days or a month. In the end, the only thing that helps is position size. And the fact that MATT performs better in this scenario is only demonstrated by the in-sample backtest.
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@Yoshika position size, leverage, and diversification. Apart from that, there was also out-of-sample data.
It starts with the undiversified universe of levGTAA
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@SemiGrowth
Having four asset classes doesn't automatically mean the portfolio is undiversified. I find your comment about the out-of-sample data more interesting. Which data points were actually still untouched after MATT's entire optimization process?
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@Yoshika One-tenth of the data—I’m not exactly sure which part—but I did run the out-of-sample Monte Carlo test.
levGTAA does have a significant U.S. exposure. It would be interesting to know which assets contributed to which performance. Probably 3xQQQ and BTC accounted for almost everything. The assets need to continue performing as they have over the past 20 years.
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@SemiGrowth
I agree with you about the U.S. risk.
But a one-tenth holdout—where you no longer know which one it was—is kind of hard to classify as "out-of-sample." And running Monte Carlo simulations on the same historical data is, to me, more of a robustness test.
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I'm out—I still need to explain to my backtest why it's not hitting 28%... Thanks, guys ʕ•ᴥ•ʔっ♡. I'm going to light another candle for the God of Overfitting 🕯️
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@SemiGrowth @yoshika Thanks for your discussion and your questions. Yoshika, please light a candle for me too :D I tried to make a little sense of your questions for myself and answer them all at once, so I just fed the questions to the AI, and this is what came out (I actually already knew the gist of almost all the answers beforehand, but obviously I don’t know every metric by heart, so this was easier): (Backtest 1987–2026, average across all 21 possible trading days):

1) Tail risk— @SemiGrowth is right here; it’s high:
- maxDD −62% (−70% only on the last day of the month), worst month −29% (Aug. 1990), worst day −17%
- Probability of a >50% drawdown in 10 years: approx. 30%; >75%: approx. 1–2%; >90%: practically 0
While leveraged ETPs do not result in liquidation like a coin flip (no margin call; a knock-out would theoretically only be possible at −33% of the underlying asset’s value in a single day, or at 5x −20%), but you must be able to withstand losses of −60% to −80%. For me, the solution lies in position sizing and diversification across strategies.

2) Crash Timings (range across all 21 possible trading days):
- Dotcom 03/2000–10/2002: +22% (+2% to +32%); Nasdaq 100 itself −83%
- Financial Crisis 10/2007–03/2009: −4% (−23% to +14%)
- COVID 02–03/2020: −25% (−49% to −3%)
- Oct. 1987 crash: −27%, 1994 bond crash: −25%, 2022 interest rate shock: −26% (3x Nasdaq: −79%)
→ The trend filter reliably captures slow bear markets, regardless of which day trading takes place. In the case of rapid V-shaped crashes like the COVID-19 crisis, however, timing is key—and in such cases, it really is largely a matter of luck.

3) Debt crisis / Correlations: QQQ and TLT were held simultaneously on 41% of the days. Their correlation was clearly negative from 2000 to 2019 (approx. −0.3) and has been slightly positive on average since 2020 (approx. +0.2). The next historical examples of “stocks and bonds falling together” are 1994 and 2022, each with a decline of approximately −25%. A month with a −30% decline is therefore realistic. This is another reason why I’m currently allocating 3x IEF instead of 5x TLT for bonds—and also because of the costs associated with 5x TLT. The question that needs to be clarified is whether to continue using TLT as the signal provider or switch to IEF as the signal, since IEF is also the index in which we’re invested. In the future, a shift to 3x TLT—assuming it remains tradable—would be an option. Since 2020, BTC has correlated with QQQ at an average of 0.39 over a one-year period (2010–19: 0.12). The peak was 0.69 in September 2021. Since 2016, it has been above 0.5 in 24% of the months.

4) @Yoshika Contribution per asset (return contribution p.a.): Nasdaq 12.8 percentage points, TLT 7.8, BTC 7.1, gold 4.2. Nasdaq and BTC thus account for a good 60%—though this varies greatly depending on the decade: From 2000 to 2009, the majority came from gold and bonds (Nasdaq only 3.7); since 2010, it has come primarily from BTC and Nasdaq. Without the Nasdaq, the figure would be 16.4% p.a.; without BTC, 20.5%; and without TLT, 22.3%.

5) Out-of-sample: @Yoshika is right here. With levGTAA, there is also no clean out-of-sample (OOS) test; all data from 1987–2026 has been incorporated into the model, and Monte Carlo simulations on the same historical data serve as a robustness test, not an OOS test. I try to keep overfitting to a minimum (averaging parameters instead of optimizing them, plateaus, halving test, walk-forward, stress tests: BTC without trend return 23.6% p.a., bonds without interest rate tailwind 23.7%).
My comment on the AI’s response: 14-day signals were a disaster for my system, but I can’t speak for your system—it involves too much back-and-forth between assets because it switches too quickly, at the same time, it’s also a risk to include multiple highly correlated assets, since that makes back-and-forth movements between them more likely and they share a combined drawdown risk. My system, on the other hand, performs weaker when an asset underperforms over a long period. In short: no matter what you do, every system has strengths and weaknesses; I’ve decided on this approach.

This is not investment advice. It is not an advertisement for a financial product, nor is it a solicitation to buy or sell securities or certificates.
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