Value-at-risk limits force position liquidation once breached

Evidence

Paradoxically, another factor may have been modern risk-management practices, particularly value-at-risk. This allows senior management to control the risks incurred by trading desks by allocating them a risk limit, while avoiding detailed supervision of their trading. When a desk reaches its value-at-risk limit, it must start to liquidate its positions. — Donald MacKenzie, An Engine, Not a Camera, 1048

Categorization

• DEFINE: Clearly defines value-at-risk as a risk-allocation mechanism that mechanically triggers liquidation.
• CANDY: The trader’s quip that banks are managed by accountants who mechanically close positions is a memorable light fact.
• XREF: connects to: Regulatory AAA requirements forced funds to buy the very derivatives that collapsed. — Mark Blyth, Austerity: The History of a Dangerous…, 93; An unaccountable liquidating desk accelerated losses that hit all consensus traders — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 1034; Investor redemptions, not trader conviction, forced hedge funds to unwind losing positions — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 1046 (+5 more)

Broader Connections

• Value-at-risk quantifies portfolio exposure through estimated loss probabilities. #expands (0.85) — Donald MacKenzie, An Engine, Not a Camera, 995
• A small trigger can unravel large systems of overlapping arbitrage positions through forced selling #expands (0.80) — Donald MacKenzie, An Engine, Not a Camera, 156
• Limited arbitrage capital can force abandonment of even certain-profit trades #expands (0.75) — Donald MacKenzie, An Engine, Not a Camera, 1217