Reactive portfolio performance attribution: decompose a drawdown into market/regime, factor/thematic, and stock-specific components. Also called 'drawdown attribution' or 'performance attribution' in PM/RIA vocabulary. Uses score-vs-price divergence to determine if the loss is fundamental or transient, then gives conditional advice. Triggered when a client asks 'why am I down X%?'. Holdings as [{symbol, weight}]. NOT for proactive health checks (use /parallax-portfolio-checkup), not for forward-looking reviews (use /parallax-client-review), not for hypothetical scenarios (use /parallax-scenario-analysis), not for trade recommendations (use /parallax-rebalance).
