Bitcoin opened September lower, dropping about 1% to below $78,000 as the market entered the month commonly labeled “Rektember” because of its historically weak performance.

Since 2013, September has been Bitcoin’s weakest month on average, with the cryptocurrency losing around 3% and posting positive returns in just five years.

There are, however, signs that this year could break from the pattern. BTC has gained in each of the previous three Septembers. Even so, its 25% jump in August, the strongest monthly increase since November 2024, leaves the market vulnerable to profit-taking, consolidation or a deeper pullback.

The economic backdrop is adding to those risks. Federal Reserve Chair Kevin Warsh used his Jackson Hole speech last Friday to highlight persistent inflation concerns, taking a stance that helped drive selling across global government bonds. Several sovereign yields have since climbed to fresh cycle highs.

The benchmark U.S. 10-year Treasury yield reached 4.784%, while traders now see a 66% chance of a 25-basis-point Fed rate hike on Sept. 16. Expectations for another increase later in the year could take the federal funds target range to 4.00%-4.25% by the end of 2026.

Rising interest rates can weigh on Bitcoin and other risk assets by tightening financial conditions and supporting the U.S. dollar. Other traditional assets have also come under pressure, with gold losing more than 2% on Tuesday.

Geopolitical developments are adding to market uncertainty. Continued U.S. strikes against Iran have increased tensions in the Middle East, pushing WTI crude oil about 2% higher over 24 hours to around $88 per barrel, its highest level since late July.

September has historically been difficult for equities as well. Since 1975, it has been the only month when the S&P 500 has posted a negative average return.

After Bitcoin’s powerful August advance, the combination of seasonal weakness, higher Treasury yields and expectations for tighter Fed policy could make September a key test for the cryptocurrency’s recent rally.