Reports Disagree on BlackRock IBIT’s Sept 21 ETF Inflow

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CryptoBriefing and CoinDesk both cover Sept 21 spot Bitcoin ETF inflows totaling roughly $999M, but give conflicting figures for how much of that went to BlackRock's IBIT.

CryptoBriefing and CoinDesk both cover Sept 21 spot Bitcoin ETF inflows totaling roughly $999M, but give conflicting figures for how much of that went to BlackRock's IBIT.

What all sources agree on

  • US spot Bitcoin ETFs recorded net inflows of approximately $999 million on September 21.
  • BlackRock's IBIT led the day's inflows among spot Bitcoin ETFs.
  • Bitcoin's price rose during this period, with CryptoBriefing citing levels above $81,000 and CoinDesk citing a rise to $85,000 this quarter.

Where the reports disagree

1Amount BlackRock's IBIT took in on September 21

IBIT alone attracted approximately $618 million, a figure that puts it comfortably ahead of the rest of the field.

CryptoBriefing

BlackRock's IBIT led Monday's inflows with $381.37 million, followed by Ark's ARKB with $289.12 million and Fidelity's FBTC with $238.84 million.

CoinDesk

What would settle it: BlackRock's official daily fund flow disclosure or the underlying SoSoValue/Farside ETF flow data for September 21.

2Whether the ~$999M figure covers Bitcoin ETFs alone or Bitcoin plus Ether ETFs combined

US spot Bitcoin and Ether ETFs pulled in a combined $1.269 billion in net inflows on that single trading day, with BlackRock's iShares Bitcoin Trust leading the charge.

CryptoBriefing

U.S.-listed spot Bitcoin exchange-traded funds drew a net $998.95 million on Monday, their largest daily inflow since bitcoin reached a record high on Oct. 6, 2025.

CoinDesk

What would settle it: SoSoValue or Farside's separated daily flow tables for spot Bitcoin ETFs versus spot Ether ETFs on September 21.

What to make of it

Treat the roughly $999 million total spot Bitcoin ETF inflow figure for September 21 as broadly agreed, but do not rely on either outlet's specific IBIT dollar amount ($618 million vs. $381.37 million) until checked against the underlying fund flow data.

Treat the roughly $999 million total spot Bitcoin ETF inflow figure for September 21 as broadly agreed, but do not rely on either outlet's specific IBIT dollar amount ($618 million vs. $381.37 million) until checked against the underlying fund flow data.