Bitcoin ETFs have gained significant traction as institutional portfolio alternatives, driven by low bond yields and inflationary pressures. Since the US SEC's approval of spot Bitcoin ETFs in January 2024, the market has experienced substantial growth. By early February 2025, US spot Bitcoin ETFs recorded over $40.6 billion in net inflows, a 175% increase from the previous year. BlackRock has recommended a 1-2% allocation to Bitcoin for portfolio diversification and return enhancement, with its IBIT fund seeing a record $6.35 billion in net inflows in May 2025. A study by ARK Invest and 21Shares indicates that a 5% Bitcoin allocation in a traditional 60/40 portfolio could boost annualized returns by over 3%, highlighting the potential of Bitcoin ETFs as a diversification tool in a low-yield environment.