Bitcoin nears a September gain that would break a 13-year pattern

Bitcoin is on course to finish September higher, a result it has not managed after a positive August since 2013. The coin traded near $84,000 on 29 September 2026, up about 7% for the month, with two trading days left.

CoinDesk analyst James Van Straten laid out the pattern on 29 September, using Bitcoin's monthly returns. Every positive August since 2013 has ended with a losing September. Break the run this week, and Bitcoin books its third monthly gain in a row, after July and August.

What the monthly numbers show

Bitcoin rose about 25% in August. It added roughly 7% more in September, CoinDesk reported. Yahoo Finance measured the one-month move at 7.3%, close enough to tell the same story. The coin opened 29 September at $83,488 and changed hands at $83,961.10 by 11:06 UTC, according to Yahoo Finance. CoinDesk had it near $84,000 at 09:45 UTC. Small numbers, long memory.

CoinDesk framed the move as a chance to break a decade-long streak. The point is not the size of the gain. It is the calendar. September has been Bitcoin's weak month for years, and a winning August had reliably given way to a losing one.

Ethereum moved the same way. The second-largest coin opened 29 September at $2,687.61 and traded at $2,715.40 by 11:06 UTC, Yahoo Finance data showed, up about 10% over the month. Both coins climbed together into the month's final days.

The bond market is pulling the other way

Rising government bond yields are the main drag. The U.S. 10-year Treasury yield sat above 5.2%, CoinDesk noted, near the top of its range for the year. The MOVE index, which tracks how much traders expect bond prices to swing, held above 100. Higher yields give cautious investors a paying alternative to assets that yield nothing, Bitcoin among them. BTC Newz covered the same pressure when the 10-year hit a 19-year high earlier in the week.

Why one green month proves little

Calendar patterns make tidy headlines. They rarely predict much. A single winning September, coming after 12 years of the reverse, is a thin sample. Patterns are not promises. Traders who read it as a signal are guessing, not measuring. Fund flows have moved both ways this quarter, and spot Bitcoin funds only swung back into positive territory for 2026 this month. History offers one comparison. CoinDesk noted the fourth quarter has been Bitcoin's strongest stretch, with an average gain near 77%. That average hides deep drops inside otherwise green quarters. No one can say this year will follow the script.

What to watch

Two trading days remain. A sharp drop before the 30 September close could still turn the month red and keep the 2013 pattern intact. Watch the bond market first. If the 10-year yield keeps climbing, it competes harder for the same cash. The October open will show whether buyers treat a green September as a green light or a reason to sell the news. Neither CoinDesk nor Yahoo Finance offered a price forecast, and past quarterly averages are not a plan for this one.