Bitcoin exchange reserves have hit a three-year low, with only 2,825,703 BTC left on exchanges, according to CryptoQuant data. This drop indicates low selling pressure and potential supply shocks. The approval of Bitcoin ETFs in the US has increased pressure on Bitcoin's supply, with asset managers like BlackRock accumulating significant amounts. Despite recent outflows from Bitcoin investment vehicles, industry experts predict institutional capital will continue to flow into Bitcoin. Furthermore, Bitcoin's supply is constrained by the recent halving event, which reduced the block mining reward.