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The mathematics of leverage — why borrowed money magnifies volatility

June 14, 2026 · 7 min

Ryan Castillo & Jordan Hale

LTCM's positions were mathematically sound by every valuation metric—the Nobel laureates running it knew the math cold—yet the fund lost $4.6 billion in four months anyway, and the number that matters here is not the loss, it's the leverage: they were running somewhere north of 25-to-1. Wow — and, like, that's what gets me every…

Financial leverage is the use of borrowed capital to control a larger asset position than equity alone would permit, mechanically multiplying returns on equity (ROE) when the asset return exceeds the cost of debt, and destroying equity when the reverse holds.

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About this episode

Financial leverage is the use of borrowed capital to control a larger asset position than equity alone would permit, mechanically multiplying returns on equity (ROE) when the asset return exceeds the cost of debt, and destroying equity when the reverse holds.

Grounded in 12 sources
Mapping Microscopic and Systemic Risks in TradFi and DeFi: a literature review · arxiv.org
The Impact of Volatility Targeting · doi.org
The great margin call: The role of leverage in the 1929 Wall Street crash - Borowiecki - 2023 - The Economic History Review - Wiley Online Library · onlinelibrary.wiley.com
Chapter 10 Hedge Funds and the SEC: Observations on the Why and How of Securities Regulation in: Current Developments in Monetary and Financial Law, Vol. 5 · elibrary.imf.org
[PDF] Leverage in Private Equity Real Estate · aeaweb.org
Leverage · meketa.com
[PDF] VALUE-ADD REAL ESTATE - CBRE Investment Management · cbreim.com
Financial Leverage for Enhanced Returns | 37th Parallel Properties · 37parallel.com
What Is Financial Leverage, and Why Is It Important? - Investopedia · investopedia.com
Leveraged Return Calculator: How Leverage Amplifies Returns — Principles, Risks & ETF Decay · stocktoolhub.com
Leverage in Commercial Real Estate: Effects on Risk & Return | Ryan OConnell, CFA · ryanoconnellfinance.com
Gearing: How debt amplifies private equity losses · auxiliamath.com
Read transcript

Ryan Castillo: LTCM's positions were mathematically sound by every valuation metric—the Nobel laureates running it knew the math cold—yet the fund lost $4.6 billion in four months anyway, and the number that matters here is not the loss, it's the leverage: they were running somewhere north of 25-to-1.

Jordan Hale: Wow — and, like, that's what gets me every time I come back to this story, because these were not reckless people, they were the people who literally wrote the equations, and it still didn't matter.

Ryan Castillo: Right, and that's the thing — leverage doesn't fail when the analysis is wrong, it fails when the market runs out of patience, and those are completely different failure modes.

Jordan Hale: It's — the way I think about it is, you can be correct about where a trade ends up and still get wiped out before it gets there, which is kind of a terrifying idea if you sit with it.

Ryan Castillo: So what does that mean for anyone using leverage today — in equities, real estate, wherever — is what we're getting into, because the math here is genuinely invariant, it doesn't care what era or asset class you're in.

Jordan Hale: Yeah, and when you zoom out, that's actually the whole episode — it's not a warning about being smart enough, it's a warning about time, and who controls how much of it you have.

Jordan Hale: Long-Term Capital Management. 1998. Nobel laureates running the fund. And they were right — like, their convergence trades on sovereign bonds were analytically correct. But they lost $4.6 billion in under four months anyway.

Ryan Castillo: Right. And that's the thing people miss. LTCM didn't fail because the math was wrong. It failed because at 25-to-1 leverage, you don't control the position anymore. The creditor does.

Jordan Hale: Which is so brutal, because imagine being in that room. You know you're right. The model says you're right. And the market just — it won't let you stay right long enough for the math to resolve.

Ryan Castillo: Here's the thing — let's actually run the formula so we know what we're talking about. ROE equals ROI plus the spread between ROI and your interest rate, multiplied by your debt-to-equity ratio. So: borrow half at 5%, invest at 10%, your equity return is 15%. Clean. The DuPont analysis calls this the equity multiplier — assets divided by equity. It scales every outcome.

Jordan Hale: Okay but now flip it.

Ryan Castillo: Same 50% leverage, asset loses 10%. Your equity loss isn't 10% — it's 25%. The debt service is fixed. It doesn't care that the asset dropped. That asymmetry is structural. It's baked into the formula, not into investor psychology.

Jordan Hale: I'd actually push back on that slightly. Like, yes, the math is symmetric — loss amplification is structural. But people don't deploy leverage symmetrically. They lever up when confidence is high and volatility is low. So there's a behavioral selection bias on top of the math. The 2015 Chinese stock market crash — retail investors piling into margin accounts at the top — that's not a formula problem, that's a timing problem.

Ryan Castillo: The 2015 China crash is actually a perfect example of both things happening at once. The second-largest equity market in the world, down 40% in one month. Excessive retail margin lending created the forced-liquidation cascade. The behavioral piece got it started — but the mechanism that turned a correction into a systemic crash? That's pure forced selling. Margin calls begetting more margin calls.

Jordan Hale: Which is the same thing that happened in 1929. Same spiral, totally different era, different asset class.

Ryan Castillo: Exactly — and that's the point. The forced liquidation spiral isn't a product of the regulatory era or the asset class. Collateral values fall, lenders raise margin requirements, you sell into a declining market, prices fall further, more margin calls. It's self-reinforcing. It happened in 1929, LTCM in '98, China in 2015.

Jordan Hale: But Ryan — doesn't that actually support my point? If it keeps happening across completely different eras and regulations, isn't the repeating variable human behavior, not an unsolvable math problem? Like, shouldn't better margin calibration have fixed this by now?

Ryan Castillo: Margins are chronically miscalibrated. Look at BitMEX — Bitcoin futures data shows that to limit daily forced liquidation probability to 1%, you need a 33% margin requirement. Most exchanges run 1% to 2%.

Jordan Hale: Wait, 3.51% of long contracts liquidated in a single day—

Ryan Castillo: At extreme leverage levels, yes. 60x average leverage. At 1% margin that's not a tail event — that's Tuesday. The exchanges set margins for normal market physics. Crises run on different physics entirely.

Jordan Hale: That's wild. So volatility targeting — Harvey's research showing you scale leverage down when volatility rises — that actually works?

Ryan Castillo: It reduces left-tail severity for equities and credit. But the research doesn't hold for bonds and commodities. Which, look, if the leverage mechanism is identical across all asset classes — and it is, the formula doesn't change — why does the risk management only work in some of them? That's a real gap.

Jordan Hale: Okay and there's also the Acadian finding — higher-leverage portfolios can actually produce higher information ratios and less active risk than lower-leverage ones. Which sounds insane.

Ryan Castillo: It's a real finding. But I want the denominator. Show me the funds that used 'smart leverage' and blew up anyway. Survivorship bias is doing heavy lifting in that story.

Jordan Hale: Which loops right back to LTCM. Because here's something that I don't think gets said enough — their creditors lent them money at 25-to-1 because they were Nobel laureates. An anonymous fund with identical positions could never have borrowed at that scale. So reputation was its own leverage multiplier. The formula doesn't capture that.

Ryan Castillo: That's a real point. But the structural argument holds regardless. Any entity with 25-to-1 leverage and illiquid positions is a liquidation waiting for a trigger. The credibility got them the rope. The leverage is what hung them.

Jordan Hale: I think both things are true and that's what makes it so hard to fix. The math is solved. We know it. We've known it since 1929. And yet — every generation finds a new story for why this time they can hold the position long enough.

Jordan Hale: Man, okay. What gets me — like, what I keep coming back to — is that LTCM had the Nobel laureates. They had the math. And the math was right. The trade was right. They just ran out of time. And somehow that's supposed to be the cautionary tale that fixes it, but it clearly isn't, because here we are.

Ryan Castillo: Here's the thing — the math being right is almost the most dangerous version of this. Because it gives you conviction to hold on. And conviction plus leverage plus a market that doesn't care about your timeline is how you lose everything on a trade that eventually pays off for whoever bought it from you at the bottom.

Jordan Hale: So the real question — the one I don't think anyone's actually sitting down to answer — is whether a market that needs leverage to function can survive the leverage failing. Like, structurally. Can it. We'll be back.

The mathematics of leverage — why borrowed money magnifies volatility · Onpode