Treasury Secretary Scott Bessent is set to reveal how far he’s initially willing to go restrain US bond yields via an expanded buyback program that has Wall Street dealers on edge. The Treasury Department is expected to announce on Wednesday the size of the next day’s operation to repurchase outstanding 10-year to 20-year securities; past precedent indicates it would be at 11 a.m. in Washington. It will be the first such release since the Treasury shocked market participants Aug. 19 by saying it would “at least double” the $2 billion sizes it had penciled in just two weeks before.

Market participants are closely watching for signals on the scale and timing of the intervention, which aims to moderate long-term yields amid persistent volatility in government debt markets.