Excess Returns Podcast Summary

Episode Title: The Liquidity Trap Door | Cem Karsan on Why We Are Likely in a Bubble, It Could Get Bigger, And What Pops It
Date: October 31, 2025
Host(s): Justin Carbonneau & Jack Forehand (Excess Returns)
Guest(s): Cem Karsan (Kai Volatility Advisors), Dave Nadig (ETF.com)

Episode Overview

This episode centers on the current “bubble” conditions in financial markets, with an in-depth exploration of liquidity’s role, the growing influence of options, the dangers of recency bias, and how long-term investors should think about risk management in structurally elevated and uncertain markets. Cem Karsan warns of “fat tails” and the limitations of traditional 60/40 portfolios, making a case for more diversified, risk-aware investment frameworks. The discussion also covers the explosive rise of AI-related investments, historical analogies, and portfolio construction for today’s environment.

Key Discussion Points and Insights

1. Are We in a Bubble? Understanding Market Altitude and Liquidity

(03:04–07:29)

• Karsan’s Metaphor: Today’s stock market resembles a plane flying at a dangerously high altitude (“70,000 ft off the ground”). The current level (altitude) is determined by fundamentals, but what keeps the plane flying is “gas”—market liquidity.
• Short-term vs. Long-term: Fundamentals matter over a decade, but in the short run, supply/demand and liquidity dominate price action.
• Liquidity as the Critical Factor: Liquidity isn't just provided by central banks or treasuries, but increasingly comes from markets themselves.
• Bubble Dynamics: The bubble can still grow larger; being aware of it doesn’t mean it’s wise to short it. Instead, manage your risk, because “when the gas runs out, the fall will be much greater than ever imagined.”
• Quote:

  “In the short term, all that matters is the amount of gas in that tank, the amount of liquidity for markets, the amount of buyers versus sellers. That’s what matters. And that’s why we look at the markets and say, ‘how could this possibly go any further?’ And it just goes to incredible altitudes.” – Cem Karsan (06:35)

2. Options: The (Hidden) Dog That Wags the Market

(07:29–19:14)

• Not Just a Derivative: Options are not merely a tail wagging the dog (the cash market)—they’re crucial in price-setting because they express the full probability distribution of outcomes.
• “Three Dimensions, Not Two”: Options trading is superior in expressing nuanced market views, and liquidity/market structure changes (explosive growth in zero-day options) are transforming how markets work.
• Reflexivity: The act of hedging or insuring market movements via options actually impacts market probabilities, unlike traditional insurance in the real world.

  "Owning insurance for tornadoes doesn't affect the odds of a tornado coming through town... That is not true in financial markets. Owning market insurance has significant, meaningful effects on supply and demand." – Cem Karsan (13:54)

• Retail and Complexity: Retail flow has flooded options in recent years, which creates both more pricing precision and new risks due to regulatory, structural, and educational gaps.

3. Reflexivity in Markets Explained

(15:14–18:54)

• Definition: Reflexivity is the feedback loop where market participants’ hedging or speculation actually alters the outcome distribution and, thus, the underlying asset’s price/volatility.
• Example: If put prices fall, the expected value of the stock rises, and vice versa. Options flows can directly impact underlying volatility and prices.
• Practical Implication: Investors must think in terms of probability distributions, not simple up/down projections.
• Quote:

  “If you do that, what do I think it’s in a month, what do I think in a week, what do I think in a year? You’ve drawn a broad distribution and that is your opinion of that asset, which is way more nuanced than up/down.” – Cem Karsan (17:46)

4. Common Pitfalls: Misunderstanding Options & Complexity

(18:54–22:14)

• Investor Laziness: Many investors skip proper due diligence, especially when using packaged option products, leading to misuse and poor outcomes.
• AI’s Role: AI may soon make precise, probability-driven thinking about options more accessible to non-professionals, accelerating broader adoption.

5. Macro & AI: What Does the Buildout Mean?

(22:39–30:06)

• Liquidity and the Asset Bubble: Asset appreciation itself is the biggest generator of new liquidity, fueling further investment in AI and data infrastructure.
• Watching History Repeat: Karsan draws parallels to the dot-com era—exuberant investment, unrealistic return assumptions, and geopolitical imbalances.
• Private Markets Signal: Early troubles in private equity and credit are a warning. Market liquidity allows bubbles in public markets, but private markets (“illiquid premium”) may prove vulnerable first.
• Quote:

  “If you are betting on 5 to 10 year outcomes, which is what’s happening here with these investments, these aren’t one year investments, you should probably be a little more cautious.” – Cem Karsan (24:56)

6. What Will Pop the Bubble? What Should Investors Watch?

(30:06–36:55)

• Liquidity is the Core Indicator: The best predictor for market risk in the short-term is tracking liquidity and knowing which events might cause it to suddenly contract.
• Risk Dashboard: Investors should monitor:
  • Global conflict (e.g. China/Taiwan, which could hit Nvidia hard)
  • Diverging performance between private and public markets
  • Structural inflation reappearing (break-evens, bond yields)
  • Seasonal and regulatory shifts
• Fat Tails: Both downside (left tail) and upside risks are underpriced in the current market—active risk management is essential.
• Quote:

  “At baseline you need to think about the world distributionally and hedge those risks.” – Cem Karsan (30:56)

7. The Case Against 60/40 and for True Diversification

(36:55–64:19)

• Historical Perspective:
  • Over 125 years, the S&P 500 Sharpe ratio is 0.35; for 60/40 portfolios, it's just 0.37—indicating almost no diversification benefit historically.
  • The outperformance of 60/40 is entirely linked to the 40-year bond bull market (1982–2022); this is likely a historical anomaly.
• Recency Bias: The post-1982 period’s success has warped investor expectations; investors ignore the periods when diversification failed (e.g., rising rates in 1968–1982).
• Quote:

  “There is zero diversification benefit of bonds relative to stocks over the long run. Zero.” – Cem Karsan (37:50)

• Portfolio Construction Recommendations:
  • Reduce equity overweight (not 60% stocks)
  • True diversification across uncorrelated strategies (not just ‘alternatives’ like private equity/credit/real estate)
  • Always hold some long volatility (“tail risk”)—5–10% allocation

    “Long vol is brakes on a race car...Brakes win races because they allow you to go faster.” – Cem Karsan (56:46)

  • Use options strategically—e.g., box spreads as bond alternatives for better risk-adjusted yield
  • Focus on risk-adjusted returns (Sharpe ratio), not just nominal performance
  • Apply a mix of thematic (interest-rate-resilient) stocks and non-correlated trading strategies (managed futures, merger arb, etc.), with active rebalancing using a value focus

Notable Quotes & Memorable Moments

• On Bubble Dynamics:

  “You can simultaneously be very bullish in the short term…while still being 70,000ft off the ground and knowing that when that gas tank does inevitably go dry, that the decline is going to be way bigger than you could ever imagine.” – Cem Karsan (04:19, repeated thematic point)

• On Reflexivity:

  “Owning market insurance has significant, meaningful effects on supply and demand of whether the underlying asset actually realizes or doesn’t realize.” – Cem Karsan (13:54)

• On Recency Bias:

  “Should we look at a data set that’s a little broader than that [1982–2022 40-year bull]?...We are living in a world of dramatic recency bias because nobody looks at anything longer than 10 years, 15 years.” – Cem Karsan (39:32)

• On the Unchanging Nature of Financial Gravity:

  “It is bigger. I said it is bigger. It is more extreme than we’ve ever done...That back will be bigger. It is still subject to gravity. That’s the point I’m trying to get across.” – Cem Karsan (44:54)

• On Why Avoid 60/40:

  “97% of the world is doing X. These are advisors that are like advising their clients, but nobody understands the risk of what they own.” – Cem Karsan (37:34)

• On Risk & Portfolio Construction:

  “If you can make 10 to 12% annualized consistently, why would you opt for something that over 125 years makes 10% with five times the risk?” – Cem Karsan (62:33)

Timestamps for Important Segments

| Time | Segment Topic | |------------|-------------------------------------------------------------| | 03:04 | The Bubble Metaphor: Planes & Gas (Liquidity) | | 07:29 | Options: The New Market Dog & Three-Dimensional Thinking | | 15:14 | Explaining Reflexivity & Distributional Thinking | | 18:54 | Investor Pitfalls: Misusing Options & Recency Bias | | 22:39 | AI Infrastructure Bubble; Parallels to Dot-Com Era | | 30:06 | What Pops the Bubble? How to Watch for Danger | | 36:55 | The Myth of Diversification: 60/40 Under the Microscope | | 51:37 | From Macro to Portfolio: Practical Recommendations | | 56:46 | Long Vol/Options for Risk Management in Portfolio | | 62:33 | Why Risk-Adjusted Returns Matter More Than Nominal Returns |

Conclusion

This episode presents a sophisticated, dynamic take on financial markets in 2025, emphasizing that today's investor must move beyond simple up/down forecasts and outdated allocation models. The critical variable is liquidity—both its abundance and its sudden, unpredictable withdrawal. Options are now central to understanding and exploiting market risk, and reflexivity amplifies feedback loops. For investors, classic 60/40 portfolios are unlikely to protect or outperform over the next decade. Instead, true diversification, active risk management, and nuanced, probability-based thinking are paramount for survival—and potential outperformance—as we fly through increasingly rarefied financial air.