Bitcoin ETF Streak Snaps: $462.7M Outflow Week
The week in flows
US spot Bitcoin ETFs shed -$462.7M net over the four sessions from September 8 through September 11 — Monday, September 7 was Labor Day, so this was a short week — ending three consecutive positive weeks with the category's worst reporting period since the rally began in mid-August. Every session was negative: -$46.6M on Tuesday, September 8, -$120.2M on Wednesday, -$282.7M on Thursday, September 10, and -$13.2M on Friday. bryptoflows' own flow-streak tracker puts the current run at 4 sessions negative — the entire reporting week, with no green day to offset it.
Thursday did almost all the damage. Its -$282.7M print carried a z-score of -1.24 against the fund's full history, in the 10.5th percentile of every session since inception — not the worst day on record, but a genuinely weak one, and it landed with breadth at its narrowest point of the period: one product positive, six negative, five reporting exactly zero. KuCoin's same-day coverage and Coinpaper's reporting both put the day's total at the same $282.7M level bryptoflows tracks, tying the move to bitcoin sliding toward $77,000 ahead of Friday's CPI print. CryptoTimes reported the three-day total through Thursday at roughly $449M, consistent with bryptoflows' own -$449.5M figure for September 8 through 10.
Every rolling window bryptoflows tracks turned with the week. The five-session average is now -$57.6M a day, a sharp reversal from +$197.3M a week ago, though the ten-session average of +$32.2M and twenty-session average of +$165.5M are still positive — a reminder that this week's weakness has not yet erased the strength of the four weeks behind it. The flow-acceleration reading, which measures the change in that short-term trend, sits at -179.7, compared with +12.4 a week ago — one of the sharper single-week swings this column has recorded. Friday's own session, in isolation, was unremarkable: a z-score of -0.32, in the 39th percentile of all 685 sessions on record. The week's story is concentration and consistency, not any single extreme day.
Where the selling was concentrated
One fund did roughly half the damage. ARK 21Shares' ARKB shed -$234.2M across the four sessions — 50.6% of the category's entire net outflow — including a -$164.3M single session on Thursday alone, its worst day of the period. That is a large number against ARKB's own scale: the fund's cumulative net inflow since inception is +$1,227.7M, so this single week erased roughly 19% of everything ARKB has taken in since January 2024. bryptoflows has no data on why a single week concentrated so heavily in one mid-sized product, and this recap is not speculating; it is simply the largest line in the ledger.
Grayscale's legacy GBTC was the second-largest detractor at -$129.1M, spread across three of the four sessions. Together, ARKB and GBTC accounted for 78.5% of the week's net outflow — from two funds that, combined, represent a small fraction of the category's total assets. Fidelity's FBTC shed -$50.7M, and VanEck's HODL and Invesco Galaxy's BTCO lost smaller amounts, -$13.1M and -$4.7M respectively.
The more notable line is BlackRock's own IBIT, which finished the week at -$52.5M — a small number next to ARKB's, but a meaningful one given IBIT has supplied the overwhelming majority of the category's net demand all year. bryptoflows' attribution tracker shows IBIT on its third straight negative session as of Friday's close, its longest losing streak in months. Set against a life-to-date contribution of 115.9% of the category's entire net inflow, a week where BlackRock's fund is itself a net redeemer is a different configuration than the one this column has described for most of 2026.
Two products bucked the week entirely. Bitwise's BITB finished barely positive at +$1.9M, and Morgan Stanley's MSBT was the only fund positive in all four sessions, taking in +$19.7M and extending its own streak to 4 sessions positive, per bryptoflows' tracker — a small, consistent counterweight in an otherwise one-directional week. Grayscale's newer BTC mini trust reported exactly zero flow in all four sessions, a pause after the run of positive combined-Grayscale readings this column tracked in late August. Franklin Templeton's EZBC, Valkyrie's BRRR, and WisdomTree's BTCW also reported zero across the board.
Breadth was narrow throughout, not just on Thursday: 4 of 12 products positive on Tuesday, 1 of 12 on Wednesday, 1 of 12 on Thursday, and 2 of 12 on Friday. The category's single-day product concentration reading closed the week at 0.611 on the HHI scale — elevated, though a single-day figure with only three or four products reporting any flow at all is naturally more concentrated than a broader window. Life-to-date, product concentration (0.407) and issuer concentration (0.438) are essentially unchanged from a week ago, since one bad week barely moves a two-and-a-half-year cumulative measure.
Zooming out
Cumulative net flow into the category since inception now stands at $55,223.6M, down from roughly $55.69B a week ago — this week's outflow accounts for the entire decline. The drawdown from the category's all-time cumulative peak of $62,735.9M has widened back to -$7,512.3M, or about 12.0%, up from 11.2% a week ago. That is the first week in over a month this gap has widened rather than narrowed, following three straight weeks in which it closed from 18.1% at the end of July.
Period totals: week-to-date -$462.7M, month-to-date (September) +$307.3M — still positive, entirely on the strength of September 3's record session, which this week's losses have not come close to erasing — quarter-to-date +$4,019.2M, and year-to-date -$1,370.6M, a deterioration from -$907.9M a week ago. 2026 remains a net-negative year for the category, and this week widened that gap rather than closing it, reversing the trend of the prior month.
Strategy: still no new filing, and a smaller cushion on unchanged holdings
There is nothing new to report on Strategy's treasury this week, and as with prior quiet weeks, that is worth stating plainly rather than skipping the section. The company's most recent 8-K, filed September 8 and covered in depth in Thursday's treasury piece, discloses no bitcoin purchases and no bitcoin sales for the period ending September 7, holding total holdings at 845,050 BTC against a $63.73B cost basis, or $75,412 average cost per coin. Instead of buying bitcoin, that filing showed Strategy spending $176.3M of its USD Cash pool on a preferred-stock buyback, and doubling that program's authorization to $2.0B. No 8-K has landed since, and none is expected until around September 15.
What has changed since Thursday's piece is the price the position is marked against, and it moved the wrong way. Thursday's coverage used bitcoin's $78,275 close on September 9 to put the position's unrealized gain at roughly $2.42B, or 3.8% above cost. Bitcoin has since fallen further: Yahoo Finance reported bitcoin below $77,000 on Friday morning, and Forbes Advisor's tracker put it at roughly $76,981 as this recap was written. At that level, the unchanged 845,050 BTC position is worth in the neighborhood of $65.05B against its $63.73B cost — an unrealized gain of roughly $1.3B, or about 2.1%, down from the 3.8% cushion reported just three days earlier. This comparison should be read as directional rather than precise, since it mixes bryptoflows' own SEC-sourced cost basis with a bitcoin price pulled from external trackers rather than bryptoflows' own candle feed, which is currently reporting as unavailable in the site's source-freshness check.
Financing capacity is unchanged from Thursday's reporting, since no new shares were sold this week: $44.34B of undrawn capacity across Strategy's five at-the-market programs, and $1.19B remaining under the enlarged preferred-stock repurchase authorization after this week's buyback. Neither figure has moved because neither a new filing nor new activity has occurred to move them.
What to watch
- Whether Strategy's next 8-K, due around September 15, shows a return to buying, another sale, or a fourth flat week in the past five filings.
- Whether ARKB's outsized outflow was a one-off or the start of a pattern in a fund that has otherwise run net-positive for most of its history.
- Whether IBIT's three-session negative streak extends into a fourth, which would mark the first sustained multi-week reversal in BlackRock's own fund this year.
- Whether the drawdown from the category's all-time peak keeps widening past 12%, or last week's three-month narrowing trend reasserts itself.
- The read-through from Friday's CPI print, released the same morning bitcoin fell through $77,000, into the Federal Reserve's rate decision due September 16.
- The MSCI index-exclusion consultation on Strategy, with comments due September 30 and a decision October 16, still unresolved regardless of which way the treasury or the flow data move next.
Track the flow data live on the flow pulse overview and ETF flow dashboards, and Strategy's full treasury and financing history on the MSTR breakdown. Flow, attribution, and treasury figures throughout are read directly from bryptoflows' own API — ETF flows from Farside Investors, Strategy detail from SEC filings — current through the September 11 close and the September 8 filing respectively. Bitcoin price figures in the Strategy section are sourced externally, as noted there, because bryptoflows' own candle feed was reporting unavailable at the time of writing. Retrieved and published September 12, 2026.