Sudden margin hikes can trigger forced sales that amplify the very volatility causing them

Evidence

In consequence, the use of Levy distributions means that extreme events do not suddenly increase margin requirements, which would be what would happen if the latter were based on more conventional econometric estimation. The danger of a sudden increase in margin requirements is that it may trigger forced sales, worsening the events that have caused the increase: “Suddenly there is some volatility in the market and suddenly your value-at-risk [see glossary] blows up, and `Oh, now I’ve got to do something.’ So [I’ve] got to liquidate… It’s almost likely a secondary feedback effect that adds to the volatility.” — Donald MacKenzie, An Engine, Not a Camera, 941

Categorization

• XREF: This is a concrete mechanism of procyclicality — the same feedback the book explores as financial-system effects of model choice; connects to broader financial-stability literature on margin requirements. — connects to: Regulatory AAA requirements forced funds to buy the very derivatives that collapsed. — Mark Blyth, Austerity: The History of a Dangerous…, 93; Derivatives inverted from insurance into engines that increase volatility exposure. — Aris Komporozos-Athanasiou, Speculative Communities: Living with…, 91; A small trigger can unravel large systems of overlapping arbitrage positions through forced selling — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 156 (+6 more)
• SEED: A possible essay angle: how a modeling choice (infinite variance vs. conventional VaR) acts as a systemic stabilizer in one direction and a danger in another — the hidden procyclicality of risk-management technology.

Broader Connections

• Falling collateral values triggered Bear Stearns’ liquidity crisis. #exemplifies (0.85) — Mark Blyth, Austerity, 83
• Truss’s market crash was a collateral-driven doom-loop from prior derivatives bets #exemplifies (0.82) — Yanis Varoufakis, Technofeudalism, 950
• Compressed decision time makes financial markets prone to cascading collapse #corroborates (0.80) — David Harvey, The Condition of Postmodernity, 1938
• Leverage amplifies percentage returns, making options riskier than underlying stock #expands (0.72) — Donald MacKenzie, An Engine, Not a Camera, 535
• Long capital lockups exist because arbitrage spreads can widen before converging #complicates (0.72) — Donald MacKenzie, An Engine, Not a Camera, 1041