Bitcoin was up 7.33% in September and needed to close above roughly $83,600 on Sept. 30 to secure its strongest September return in CoinGlass data going back to 2013. The gain was narrowly ahead of September 2024’s 7.29% return and would extend a run of positive Septembers that began with gains of 3.91% in 2023, 7.29% in 2024 and 5.16% in 2025. Bitcoin had closed September lower in eight of the 13 years through 2025, including six consecutive declines from 2017 to 2022, leaving the month with an average return of negative 2.34%. Bitcoin opened September near $78,500 after a 25% August advance, then fell toward $75,000 after the Senate's Clarity Act failed a 49-to-50 cloture vote on Sept. 15 and the Federal Reserve raised rates by 25 basis points to 3.75%-4% a day later. Spot Bitcoin ETFs recorded $450.4 million of outflows on Sept. 15, but subsequently attracted about $2.98 billion across seven sessions. Bitcoin then reached $87,354, its highest level since late January, amid more than $800 million in short liquidations over 24 hours. The price later retreated about 4% from that high, trading near $83,000 after Brent crude rose above $100 when President Donald Trump rejected Iran's terms for reopening the Strait of Hormuz. Bitcoin remained about 4.4% below its roughly $87,497 level at the start of 2026. The updated September performance also supports the earlier estimate that bitcoin had gained 38.90% in Q3, although the quarter remained unfinished. October averaged a 19.92% gain in the CoinGlass data, while last year's positive September was followed by a 3.69% October decline and a 23% fourth-quarter drop.