Monthly Archives: June 2026

Book Bits: 6 June 2026

How to Win a Trade War: An Optimistic Guide to an Anxious Global Economy
Soumaya Keynes and Chad P. Bown
Review via Reason
The ancient Chinese military strategist Sun Tzu advised that “he who wishes to fight must first count the cost.” Joshua, the brilliant (for its time) computer in the 1983 film WarGames, did the counting and concluded that “the only winning move is not to play.”
Both lines find their way into How To Win a Trade War. This is no arid academic analysis, and it does not read like one. Instead, Soumaya Keynes, a journalist at the Financial Times, and Chad Bown, a senior fellow at the Peterson Institute for International Economics, have crafted a witty, fast-paced analysis of how the global trading system has unraveled in the aftermath of COVID, Brexit, and (most importantly) President Donald Trump’s electoral successes.

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Research Review | 5 June 2026 | Risk Management

Measuring Bubbles via Put-Call Disparity: A Model-Free Approach
Robert A. Jarrow (Cornell U.) and Simon Kwok (U. of Sydney)
May 2026
This paper introduces simple, model-free lower and upper bounds for measuring the size of asset price bubbles. Assuming only that the market satisfies no-free-lunch-with-vanishing-risk and that all trading strategies are admissible, our framework avoids restrictive parametric models and the no-dominance assumption. We demonstrate that put-call disparity provides an observable lower bound, and is economically justified by short-sale constraints. Additionally, the lowest price of an out-of-the-money (OTM) call option determines the upper bound. To ensure empirical reliability, we modify these bounds using data-driven regularization and bootstrap methods to disentangle genuine bubble signals from market microstructure noise and to reduce reliance on thinly traded deep OTM options. Using S&P 500 index option prices from 1996 to 2025, we document a sustained bubble during the COVID-19 era and capture market exuberance preceding the 2000 dot-com and 2008 financial crashes. In addition, the empirical study suggests that the market violates no-dominance and is incomplete.

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