We collect and analyze detailed filings from global institutional investors to estimate foreign investors’ U.S. dollar (USD) security holdings and currency hedging. Over two decades, foreign USD holdings grew sixfold, while hedge ratios rose by 15 percentage points after the 2008–2009 crisis. Currency hedging across mutual funds, pensions, and insurance reached $2 trillion by 2019. Hedging demand varies across investors, currency areas, and banking systems. We show that expected FX returns, beyond variance minimization, drive currency exposure in portfolios. Finally, we demonstrate and quantify how aggregate hedging demand affects hedging costs in the presence of constrained intermediaries.