US spot Bitcoin ETFs recorded $463 million in weekly outflows, the first negative week in three weeks, putting Bitcoin's $76,000 support level in focus ahead of a Federal Reserve decision. The withdrawals removed a source of institutional demand that accompanied Bitcoin's rise from roughly $63,000 to $82,000 during the preceding three weeks. Wintermute Research shifted its outlook to neutral from constructive after Bitcoin fell $3,500, while spot Ethereum ETFs drew $197 million in weekly inflows and altcoins performed comparatively better. Bitcoin has been rejected near $82,000 three times since August and has yet to test the next major downside area around $72,000. The market is also weighing a largely priced-in September rate hike, Brent crude above $105 and a two-decade high in the 10-year Treasury yield. The latest flows follow a September 2026 Senate procedural defeat for the Digital Asset Market Clarity Act, which had coincided with a separate Bitcoin selloff and elevated exchange inflows. Analysts Justin d’Anethan and Rachael Lucas said the legislative setback represented a delay in regulatory progress rather than a structural break for crypto markets, emphasizing interest rates and monetary policy as more important medium- and long-term drivers.