On VIX>28 days the SPY intraday range medians 2.20% and QQQ 2.73% — 3x calm-tape behaviour. We don't trade risk-off by cutting size; we reprice volatility, ETF volume, and quote stability and let those decide the route.

QQQ daily range is 0.97% at VIX<13 and 2.73% at VIX>28 — nearly 3x. NVDA and TSLA scale similarly. Same share size across both regimes is the cleanest way to underperform your own setup. A dynamic-sizing framework.

VIX-implied exhaustion walls: SPY closes inside its VIX/√252 implied range on 76-95% of normal-VIX days. The wall acts as soft resistance to extension — but it breaks down at VIX >24 where realized range exceeds implied. Different regimes, different sizing.

VIX term structure: contango (VIX3M > VIX) observed on 94% of sessions 2022-2026; backwardation on the 6% that mark stress regimes. Trend continuation works in contango; mean reversion outperforms in backwardation. Same setups, opposite expected values.