Ainvest Option Flow Digest - 2026-03-18: 🐋 $107.4M Whale Wave on FOMC Day — Mega-Cap Exits, $33M Stablecoin Conviction, and a Layered S&P 500 Fortress

FOMC day delivers $107M in institutional flow across 8 tickers. Circle gets a $33M stablecoin conviction bet, mega-caps META and MSFT see $41M in call exits, and SPY draws a $17.4M layered put fortress. Full analysis inside.