The Treasury Department on Wednesday announced that it will buy back more of its own bonds, a move that partially reversed a selloff in longer-term U.S. debt that is threatening to drive up politically important interest rates on mortgages and other consumer loans.

A number of factors have been pushing up yields on longer-term debt to their highest levels since 2007, such as concern that the conflict with Iran is showing little sign of resolution, growing competition for financing with borrowers that are building out artificial intelligence infrastructure and widening U.S. government deficits.

Treasury said it would “at least double” the size of its buybacks, in which the department reabsorbs older debt securities with a maturity of at least 10 years. The previous ceiling was $2 billion per operation, and that number will be at least $4 billion, effective Sept. 9 and through Nov. 4.

The move is the latest by Secretary Scott Bessent to affect U.S. Treasury yields. Earlier this month, the department conducted a joint intervention with Japan to boost the yen, which had been trading in July at its weakest level against the dollar in roughly four decades. Bessent warned in January that turmoil in Japanese government bonds was spilling into the Treasury market.

Treasury also recently signaled the possibility that it could decide to issue less longer-term debt in coming quarters.