Bitcoin's recent price surge is tempting long-term holders (LTHs) to cash in, with Glassnode data showing a significant uptick in BTC sales from these investors. LTHs, who typically hold Bitcoin for over 155 days, have shifted to net sellers, marking the largest 30-day reduction since April. Crypto analyst Miles Deutscher warns that strong institutional buying, particularly through U.S. spot Bitcoin ETFs, is crucial to counteract this selling pressure. Despite record ETF inflows, the market faces potential sell-side pressure as Bitcoin holders sit on substantial unrealized profits.