Bitcoin ETFs accumulate $2B this week amid price rejection at $87K

US spot Bitcoin ETFs pulled in roughly $2 billion in net inflows over the past week, marking the most aggressive institutional buying spree since late 2025. The catch: Bitcoin itself briefly kissed $87,397, then promptly got rejected and slid back below $84,000.

The week's standout moment came on September 21, when spot Bitcoin ETFs recorded a single-day net inflow of approximately $999 million. That figure represents the largest one-day haul since October 2025, back when Bitcoin was riding very different momentum.

The buying didn't stop there. September 22 brought in another $715 million, followed by $347 million on September 23. Three consecutive days of heavy accumulation that, in aggregate, pushed the week's total past the $2 billion mark.

Breaking down that record September 21 session reveals the usual suspects leading the charge. BlackRock's IBIT absorbed $381 million, ARK 21Shares' ARKB took in $289 million, and Fidelity's FBTC attracted $239 million. Together, those three products accounted for the vast majority of the day's inflows, reinforcing just how concentrated the ETF market remains among a handful of heavyweight issuers.

Since August 19, cumulative ETF net inflows have reached approximately $4.6 billion. More importantly, that sustained buying has dragged 2026 year-to-date flows into positive territory at roughly +$320 million. That's a notable turnaround after what was a bruising stretch of outflows earlier in the year.