13F filers reduced their Bitcoin ETF holdings by 23% from $27.4 billion to $21.2 billion in Q1 2025.This marks the first quarterly decline in institutional Bitcoin ETF exposure since the SEC approved spot BTC ETFs in 2024.Total ETF assets decreased by 7% to $71.1 billion in the same period, contrasting with the larger drop in Bitcoin ETF holdings.Professional investors are showing caution in their Bitcoin ETF investments amidst regulatory uncertainty and shifting risk appetite.