Acadian's Lamont: August-October is prime time for market meltdowns
Owen Lamont, a portfolio manager at Acadian Asset Management, warns that August through October is historically a dangerous period for markets, with many major crashes occurring then. He points to low trading liquidity during summer vacations as a key amplifier of shocks. Lamont advises investors to mentally prepare for potential 'epic financial disasters' during this window.
Lamont's warning draws on a career spanning both academic and institutional finance. He has taught at Harvard, Yale, Chicago, and Princeton, and currently works at Acadian, a quantitative firm managing roughly $195 billion in assets. His analysis cites a specific probability calculation: approximately a 10% chance of a major market disruption between August and October, versus only about 2% during the rest of the year.
The historical record he assembles is extensive, reaching back to America's first speculative bubble in 1791 and including the panics of 1857, 1873, and 1907. He traces the seasonal pattern to agricultural cycles, when western banks withdrew funds from eastern financial centers during harvest season. This observation was documented as early as 1884 by economist William Stanley Jevons and later formalized in Oliver Sprague's 1910 history of banking crises. The Federal Reserve's creation was partly a response to these recurring autumn panics.
This seasonal warning could affect how both institutional and retail investors approach portfolio positioning during late summer and early autumn. Nervousness about the August-October window may prompt some to reduce exposure or hedge positions, potentially creating the very volatility they fear. Individual retirement savers could be influenced by such forecasts, though historical patterns do not guarantee future outcomes. The analysis may also shape how financial media frames market movements during these months, amplifying attention on any downturn that occurs.