A large inflow on the final trading day of last week was enough to spare US spot bitcoin ETFs a second straight negative week, according to The Block. Investors added $433 million to the publicly traded bitcoin products on Friday, leaving an overall $6.2 million net inflow for the week ending September 18, based on The Block's analysis of SoSoValue data. The net figure is modest but a sharp turnaround from the $462.7 million in outflows the funds logged the prior week. Spot ether ETFs were less fortunate, posting a $140 million weekly outflow despite taking in $143.8 million on Friday — ending a four-week inflow streak in which they had collected a combined $1.94 billion.

Bitcoin ETFs clawed back a large mid-week deficit: a $160 million inflow on Monday was followed by withdrawals of $450.3 million on Tuesday and $296 million on Wednesday, and even after $159.5 million came in Thursday, the funds were down $426.8 million for the week. Friday's buying covered that shortfall with little to spare, and the $433.0 million was the largest daily inflow since September 3, when they drew $730.9 million. Fidelity's FBTC — the second-largest such fund by assets and volume — accounted for $310.7 million of Friday's total, with BlackRock's IBIT adding $108.4 million and Bitwise, VanEck and the ARK 21Shares fund bringing in smaller amounts.

Over the full week, IBIT took in $120.7 million, ahead of FBTC's $79.9 million, while the other bitcoin funds together lost about $194.4 million, leaving the category barely positive at $6.2 million. Bitcoin ETFs are still down roughly $1.45 billion in net flows this year, with cumulative inflows since launch at $55.16 billion and net assets of $102.53 billion on Friday. Bloomberg ETF analyst Eric Balchunas noted the investors' resilience, saying cumulative inflows held near $55 billion after peaking around $63 billion and describing it as "incredible intestinal fortitude" given a 50% drawdown, while suggesting rising stock prices may have helped holders stay put.

For ether funds, three straight negative sessions from Tuesday through Thursday drained $404.8 million and ended the streak. Inflows on Monday and Friday were not enough to recover: BlackRock's ETHA drew $114.3 million on Friday but ended the week with $56.1 million in outflows, while Fidelity's FETH lost $25.8 million despite a $26.2 million Friday addition. It was ether ETFs' first weekly outflow since the week ending August 14, though they remain positive for the year with about $922 million in net inflows, holding $16.72 billion in net assets against $13.25 billion in cumulative inflows. Trading volume rose across both categories — bitcoin ETF volume reached $16.17 billion from $8.77 billion, and ether ETF volume $6.82 billion from $5.14 billion — aided by an extra trading day after the prior week's session count was cut to four by Labor Day.