Analysts from K33, Nexo, and 21shares point to strong institutional and ETF inflows, including nearly $1 billion into spot BTC ETFs, as key drivers behind Bitcoin's recent surge above $80,000. K33 notes the largest daily ETP inflow since November 2024, believing the cycle low is established and BTC still has room to catch up with gold and equities. The SEC's Innovation Exemption and CFTC's regulatory progress are seen as tailwinds. However, Nexo remains cautious, citing thinning volume, narrowing market breadth, and derivatives positioning that could leave BTC vulnerable to profit-taking. Fundstrat's Tom Lee believes a crypto bull market has begun.