Definition. This chart shows the average cost basis of deposits into the US Bitcoin spot ETFs — the running average price at which coins have flowed into the ETF vehicles since their launch in January 2024. Cost basis lines are shown for BlackRock IBIT, Grayscale GBTC and Fidelity FBTC individually, and for all US spot ETFs combined (green), alongside the BTC price (black).

Technical. Each cost basis line combines daily BTC inflows into the ETF with that day's price to form a running average entry level:

• Cost Basis = cumsum(Inflow x Price) / cumsum(Inflow)

Only positive flow days (net inflows) are accumulated; outflow days do not alter the average. The per-issuer lines use the IBIT, GBTC and FBTC flow subsets, and the combined line uses total flows across all US spot ETFs.

Interpretation. The cost basis approximates the average on-ramp price of capital that entered Bitcoin via the spot ETFs, making it a useful reference level for the profitability of the ETF investor cohort. When price trades above a fund's cost basis, the average ETF entry is in unrealized profit; extended periods below cost basis put the average ETF buyer underwater, a condition that has historically pressured flows. The spread between issuers reflects the differing timing of their inflows — funds that absorbed most of their coins early in a rally carry a lower cost basis than funds that attracted capital later. Note that GBTC converted from an existing trust, so its line reflects only post-conversion inflow days, which have been comparatively rare given its persistent outflows.

Notes. Built from US Spot ETF Flows. This is conceptually analogous to on-chain cost basis measures such as the Realized Price, applied to the ETF cohort specifically.