Bitcoin ETFs notch best month of 2026 as BTC gains 25% in August

US-listed spot Bitcoin exchange-traded funds (ETFs) capped their best month of 2026 alongside Bitcoin’s biggest monthly gain since November 2024.

Bitcoin ETFs attracted $3.52 billion in net inflows in August, their highest monthly total of 2026 and a sharp increase from just $172 million in inflows in July, according to SoSoValue data.

Bitcoin (BTC) gained about 25% in August, its strongest monthly performance since a 37.29% rally in November 2024, according to CoinGlass.

The August momentum quickly gave way to a weaker start to September, as ETF flows turned negative and Bitcoin briefly fell below $77,000.

August cuts year-to-date outflows by 66% to $1.77B

August’s $3.52 billion in Bitcoin ETF inflows cut year-to-date net outflows by roughly 66%, from $5.29 billion to $1.77 billion.

The biggest monthly outflows came in June at $4.51 billion, followed by $2.43 billion in May and $1.61 billion in January, according to SoSoValue data.

The funds recorded net inflows on 16 of 21 trading days in August, including nine consecutive sessions from Aug. 17 through Aug. 27.

Total net assets rose to $99.61 billion at the end of August from $76.29 billion at the end of July, an increase of about 31%. Monthly trading volume climbed nearly 49% to $58.63 billion from $39.37 billion.

September starts with $236M in Bitcoin ETF outflows

US spot Bitcoin ETFs started September with $236.46 million in net outflows on Tuesday, reversing the $216.70 million in net inflows recorded on Monday. The withdrawal marked the largest daily outflow since July 31, when the funds shed $265.37 million.

The reversal came as Bitcoin briefly fell below $77,000 on Tuesday after trading above $80,000 in late August, according to CoinGecko.