I Saw This 2x ETF System on Threads — It Comes From 3 Books

#leveraged-etf #index-investing #asset-allocation #rebalancing #books

Table of Contents

A Random Walk Down Wall Street — Hold the Index, Because Stock Picking Is a Trap
The Leveraged ETF Investing Method — Understand How 正2 Actually Behaves
The Psychology of Money — Stay Alive Long Enough to Compound
The Execution Mechanism: Rebalancing
The System’s Core Assumption — and Its Limits
The Original Poster’s System in Detail
Why These Three Books Form a System
References

🌏 中文版

I came across a post by @jj.investnote on Threads describing a long-term leveraged ETF system.

His framing: “I don’t predict the market. I don’t try to call tops and bottoms. I don’t chase hot stocks. I just designed a system that keeps running regardless of what the market does, then let time grow my assets.”

The system wasn’t invented from scratch — it was assembled from three books. Each one answers a different question: what to hold, how to accelerate, how to avoid being wiped out. Rebalancing ties all three answers into a mechanism that keeps running on its own.

A Random Walk Down Wall Street — Hold the Index, Because Stock Picking Is a Trap

Burton Malkiel’s core argument: markets are efficient (the Efficient Market Hypothesis). At any given moment, stock prices already reflect all publicly available information. This doesn’t mean markets are always rational — it means that whatever you can see, the market has already seen; whatever undervaluation you spot, so has your competition.

The conclusion is uncomfortable: most active managers can’t beat the index over the long run — not because they’re incompetent, but because markets are smarter than any individual.

The implication for investors: stop picking stocks, and instead hold a low-cost fund that tracks the entire market. In Taiwan’s case, 0050 has delivered an annualized return of roughly 12.81% since inception in 2003 — through the 2008 financial crisis, the 2020 pandemic, and everything in between. Hold for 22 years, and the cumulative return exceeds 13x.

This book settles the question of what to hold. But it also settles the question of when to trade — the answer being: never try to time the market. If even professional stock pickers can’t consistently outperform, there’s no basis for believing you can identify the right moments to move in and out of a 2x leveraged position. The correct approach is to hold and let a mechanism do the work.

The Leveraged ETF Investing Method — Understand How 正2 Actually Behaves

Lin Cheng-hua’s book (《槓桿ETF投資法》) is the first dedicated analysis of 00631L published in Taiwan. Using over 170,000 words and hundreds of charts, it unpacks two core questions about leveraged ETFs: why they decay, and why that decay doesn’t matter as much as critics claim.

Lin is a licensed insurance professional, not an academic. This shapes the book’s angle — it’s not a research paper; it’s the record of someone who spent years studying a single product, systematically answering every common objection with data.

Why This Book Exists: Life-Cycle Investing Theory

The book’s theoretical foundation comes from Yale law and finance professors Ian Ayres and Barry Nalebuff, authors of Life-Cycle Investing.

Their core argument: most people access a fixed window of stock market exposure during their lives, and that window is far smaller than it should be. The problem isn’t portfolio allocation — it’s that decades of future labor income aren’t participating in the market at all. Young people’s human capital is sitting on the sideline.

By this logic, young investors should use leverage to expand their market exposure early, then gradually delever as wealth accumulates. The goal is to smooth exposure across a lifetime rather than front-loading it in the middle decades when most people finally start “investing seriously.”

Lin uses this framework to explain 00631L’s purpose: it’s a tool for ordinary investors to access amplified market exposure at a reasonable cost — not a short-term speculation vehicle.

The Daily Reset Mechanism: Why It Can’t Go to Zero

The most common misconception about leveraged ETFs is “can it go to zero?”

The daily reset mechanism answers this: the fund recalibrates to 2x leverage at the end of every trading day. Each day starts fresh. You can’t lose everything from a multi-week crash, because each day’s loss is calculated against that day’s starting value — not your original purchase price.

Extreme example: even if the market fell 10% every day for 20 consecutive trading days, the unleveraged version would fall to 12.2 (100 × 0.9²⁰) and the 2x version to 1.15 (100 × 0.8²⁰). The leveraged version is nearly wiped out — but not zero. And the premise is also unrealistic: 20 consecutive 10% daily drops has never happened. Real crashes feature volatility in both directions, which is precisely where the daily reset mechanism limits catastrophic accumulation.

Volatility Decay Is Real

The most common criticism of leveraged ETFs is volatility decay — the daily reset mechanism means they bleed value in choppy, sideways markets, even if prices eventually return to the same level.

The math is concrete: start at 100, go up 10% then down 10%, and you land at 99 (a 1% loss). With 2x leverage: up 20% then down 20%, you land at 96 (a 4% loss). Same price path, four times the damage.

This isn’t a scam. It’s arithmetic. The book calls this path dependency — the final return depends not just on the start and end price, but on the sequence of moves in between. This is the fundamental difference between a leveraged ETF and simply doubling your position in the underlying.

Now flip the scenario: if the market keeps going up, up 10% then up 10% again, the unleveraged version reaches 121 (+21%). The 2x leveraged version reaches 144 (+44%) — more than double the gain, because compounding amplifies the uptrend.

Taiwan’s market has been exactly this kind of trending market. From 00631L’s launch in October 2014 through March 2026, its cumulative return reached 2,016% — while the Taiwan 50 Index’s total return over the same period was approximately 352%. That’s 5.7x, not 2x.

The book’s rolling return analysis reinforces this: for holding periods exceeding five years, the probability of positive returns from 00631L has historically been far higher than the probability of decay eating through principal over a comparable unleveraged position.

Why 2x and Not 3x

The book explicitly analyzes why 3x leverage is the wrong choice.

Three-times leveraged ETFs (like TQQQ in the US) suffer volatility decay at exponential rates. In a market with Taiwan’s characteristic oscillation frequency, the long-run drag from decay could eventually overwhelm the compounding advantage — making longer hold times counterproductive rather than beneficial.

More critically: 3x leverage carries a theoretical maximum drawdown above -96%. That number makes “hold and don’t sell” practically impossible for most human beings. When the crash comes, the plan gets abandoned at the worst moment. 2x leverage is the balance point — amplification meaningful enough to matter, drawdown survivable enough that the strategy can actually be executed.

The Downside Is Real Too

The maximum historical drawdown for 00631L is around -83%, compared to roughly -50% for 0050. Annualized volatility runs near 43%. During the April 2025 tariff shock, 00631L fell from approximately 250 to 125 — a 50% drop in a matter of weeks.

This is why going all-in is a trap. The book recommends pairing 正2 with a low-volatility buffer. In this particular system, the implementation uses 60% 正2 + 40% cash.

The Psychology of Money — Stay Alive Long Enough to Compound

Morgan Housel’s The Psychology of Money was published in 2020 and has since been translated into over 50 languages, making it one of the best-selling personal finance books in recent years. Housel spent years as an analyst at The Motley Fool and Collaborative Fund, but this book contains almost no financial mechanics. It’s 20 short stories, each targeting a different psychological blind spot people have about money.

Housel’s central argument isn’t “how to earn more.” It’s “how to avoid being knocked out of the game.” That’s unusually rare in investment writing — most books discuss picking the right securities; this one examines why people lose even when they’ve picked correctly.

Two Key Stories

Ronald Read: A gas station attendant in Vermont who later became a janitor. He lived frugally and quietly bought blue-chip stocks, then left them alone. When he died in 2014, his estate was worth $8 million — most of which he donated to the local library and hospital. Nobody knew while he was alive.

Richard Fuscone: Harvard MBA, former senior executive at a major investment firm, eventual bankruptcy filing.

Housel uses these two figures to make a single point: investment outcomes are not primarily determined by education, intellect, or analytical tools. They’re determined by behavior. Ronald Read won not because he was smarter, but because he stayed in the game through every bad year.

Getting Wealthy vs. Staying Wealthy

One of the book’s chapters draws a sharp distinction between getting rich and staying rich — and this maps directly onto why the 正2 system is designed the way it is.

Getting wealthy requires risk-taking, optimism, and tolerance for uncertainty. Staying wealthy requires something closer to the opposite: humility (acknowledging that part of what you earned was luck and may not persist) and a kind of productive fear (an aversion to losing what you’ve built).

Confusing the two skills is how investors who did well in a bull market give it all back. They mistake the boldness that made them money for a permanent edge, then apply that boldness at exactly the wrong moment.

The 60/40 正2 system tries to institutionalize this distinction: the leveraged position does the getting-wealthy work; the cash buffer handles staying-wealthy. Each does its job independently, without requiring the same person to hold two contradictory psychological states simultaneously.

Tails, You Win

Another chapter worth naming: “Tails, You Win.” Housel’s argument is that a small number of extreme events drive the majority of outcomes — in markets, in careers, in businesses.

Buffett’s track record is the clearest illustration: he started investing at age 10, was a millionaire by 30, and has been publicly recognized as a great investor for decades. But the overwhelming majority of his net worth — estimates suggest over 99% — accumulated after age 50. Not because he got better after 50, but because he never stopped. Compounding had decades to run.

The implication: the goal isn’t to make every decision optimal. It’s to make sure no single decision is a permanent exit. One catastrophic mistake ends the sequence. Nothing else matters after that.

This is the mathematical case for the 40% cash buffer. It’s not there to improve average returns — it’s there to prevent any single crash from being the terminal event.

Room for Error Is About Survival

Housel argues: smart planning isn’t about being more precise — it’s about deliberately building in room for error.

There’s a distinction the book draws that’s easy to miss: rational vs. reasonable. A rational plan is what pure math would prescribe — maximum expected return, optimal allocation. A reasonable plan is one you can actually sleep with, and actually execute when markets go sideways. All-in 正2 might be rational in expectation; it isn’t reasonable in practice, because the plan gets abandoned at the worst moment.

Compounding requires longevity. The investors who went all-in on stocks in 2008 and sold at the bottom never got the recovery. With a potential -83% drawdown, holding 00631L at full position is psychologically nearly impossible for most people — not because they lack discipline, but because the plan itself is unreasonable.

What the Buffer Actually Does

The 40% cash position isn’t just there to “reduce risk” in the abstract. It serves two concrete functions: it keeps you from being forced to sell during a crash, and it gives you dry powder to buy more at the lows.

With a 60:40 allocation, if 正2 drops 50%, the total portfolio falls about 30% (0.6 × 50%). That still hurts — but compared to an -83% drawdown on a full position, the psychological gap is enormous. You still have 40% in cash; you know you won’t be forced out.

In this system, the 40% cash is explicitly sized to cover four years of living expenses. That’s not an arbitrary number — the point is that no matter what the market does, real life stays unaffected. Protect your life, and you protect your ability to hold.

The Execution Mechanism: Rebalancing

The three books provide the philosophy. Rebalancing provides the execution — and it does more than just “reset the ratios.”

How Rebalancing Automatically Buys Low and Sells High

This system targets Beta = 1.2 (60% × 2x leverage = 1.2), with ±10% as the rebalancing trigger:

Beta > 1.32 (+10%): 正2 has run up too much — system triggers, sell 正2, buy cash, restore 60:40
Beta < 1.08 (−10%): 正2 has dropped too much — system triggers, sell cash, buy 正2, restore 60:40

No market calls required. The mechanism does the buying and selling for you — driven by data, not intuition.

The Trigger Is Portfolio Weight — Not Price Gain or Index Level

This is easy to misread: the rebalancing trigger is not “正2 gained X%” or “the index is at level Y.” It’s the current weight of 正2 in the total portfolio.

Example: starting with 1 million NTD — 600k in 正2, 400k in cash, Beta = 1.2. If 正2 rises 40%, it becomes 840k; total portfolio is now 1.24 million; 正2’s weight climbs to 67.7%; Beta rises to 1.35 — triggering a sell. Not because “it’s up 40% and it’s time to take profit,” but because the allocation has drifted past the limit.

The only question that matters at any rebalancing check: “What fraction of my total assets is currently in 正2?” Your purchase price is irrelevant. Whether you’re in profit or at a loss is irrelevant. Whether the index is near an all-time high or in a correction is irrelevant.

The index level only enters the picture through the crash protocol — a separate layer that activates when the broad market falls more than 20% from its peak. That’s not a day-to-day rebalancing trigger; it’s an opportunistic add-on that fires a few times per decade.

Rebalancing Produces Returns That Exceed Expectations

Lin’s back-test data illustrates this concretely: starting with 1 million NTD, going all-in on 0050 ended with a profit of roughly 570,000 NTD. Using 正2 paired with cash and executing three rebalances along the way ended with roughly 880,000 NTD — lower risk (with cash still in hand), higher return.

This is the volatility harvesting effect: the asset’s volatility itself becomes a source of returns.

The System’s Core Assumption — and Its Limits

Every investment system rests on assumptions. This one rests on one: Taiwan’s stock market trends upward over the long run.

If that assumption holds, volatility decay gets overwhelmed by trend compounding, and rebalancing keeps accumulating through the swings.

If it doesn’t — if Taiwan experiences something like Japan’s lost three decades after 1989, where the index was essentially flat for thirty years — then the volatility decay eats into principal indefinitely, and rebalancing can’t rescue it.

The system’s underlying belief is built on TSMC and the semiconductor supply chain’s global moat, the connection between Taiwan’s export-driven economy and global tech demand, and the inherent diversification of a 50-company index. But that’s a reasoned bet, not a guarantee.

Acknowledging this limit isn’t meant to undermine the system. It’s about being clear on what the system requires to work — and knowing when to revisit it.

The Original Poster’s System in Detail

@jj.investnote laid out the full execution details across three Threads posts.

Allocation: 60% 正2 + 40% cash, targeting Beta = 1.2, spread across three positions:

00631L: highest trading volume, primary vehicle for rebalancing operations
00685L: lowest expense ratio, suited for long-term holding
QLD: US 2x leveraged ETF, diversifying exposure to the US market

Ongoing rebalancing: Beta ±10% triggers the rebalance automatically. The 40% cash sits in a high-yield savings account otherwise.

Crash protocol: When the broader market drops more than 20% from its peak, deploy additional cash to buy 正2 or Taiwan index futures. Sell when the market makes a new high again. These opportunities are rare — August 2024 and April 2025 are the recent examples — but having the cash ready to act is what makes the system feel like “happy when it goes up, even happier when it goes down.”

Starting point: If leverage makes you nervous, read Lin’s book first to build conviction, then start with 30% in 正2 to test how you handle the volatility. You need to be able to sleep soundly before you can talk about returns.

Why These Three Books Form a System

Each book answers a different question:

Question	Book	Answer
What to hold	A Random Walk Down Wall Street	Total market index ETF
How to accelerate	The Leveraged ETF Investing Method	60% 正2 (00631L / 00685L / QLD)
How to avoid being wiped out	The Psychology of Money	40% cash = four years of living expenses
How to execute	All three together	Beta ±10% trigger; automatic buy-low-sell-high

Remove any one piece and the system breaks down: holding the index without leverage leaves returns mediocre; adding leverage without a risk buffer means one crash could end the game; without room for error, you’ll be forced into the worst decision at the worst moment; without rebalancing, there’s no automatic mechanism to buy low and sell high.

Together, the three books form an investment system that requires no market prediction, no willpower, and no daily monitoring.