By Karen Brettell
NEW YORK, Aug 21 (Reuters) - The U.S. Treasury's move to expand purchases of older long-dated bonds has revived a familiar worry in foreign-exchange markets: if Washington will not let borrowing costs rise, will the dollar end up absorbing the adjustment instead?
On Wednesday, Treasury said it would at least double the maximum size of certain buyback operations, raising the cap to "at least" $4 billion. The purchases target long-term securities that have faced heavy selling since
late June. On Thursday, Treasury Secretary Scott Bessent told CNBC that the buyback could be more than $4 billion and that the market "got a little bit ahead of itself" with the recent selloff.
This is not the first time the U.S. has used this tool. Treasury revived buybacks in 2024 as a liquidity-management tool for thinly traded older bonds. But the timing and scale of this announcement, coming outside the normal quarterly refunding calendar and just ahead of a 20-year auction, led some investors to read it as an attempt to relieve pressure on long-term yields.
These have climbed amid a deteriorating fiscal outlook, heavy issuance, geopolitical risk and uncertainty over the Fed's policy path. The 30-year yield this week hit its highest level since 2007 as the Iran war escalated, a day before total public debt topped $40 trillion.
The question now is whether policymakers will let markets set a higher clearing yield for long-dated debt, or instead lean on measures that could ultimately weigh on the dollar — in part by making U.S. bonds less attractive to investors and limiting related investment inflows.
"There has to be a price to pay," said Shaun Osborne, chief FX strategist at Scotiabank. "Either in the form of higher yields, or they're going to get a concession from the U.S. dollar."
CURRENCY DEBASEMENT FEARS EMERGE
Some investors see in the Treasury's actions the makings of currency debasement. The concern is not outright monetary financing — in which the central bank creates money to fund government spending — but that officials facing rising debt-service costs may try to prevent yields from reaching market-clearing levels via buybacks, shorter-dated issuance or similar tools that reduce the duration private investors must absorb.
In this case the adjustment does not vanish; it shifts, and if yields are restrained, the dollar may weaken instead — which is part of why some of the biggest gainers after Wednesday's Treasury surprise were gold, which rose more than 3%, and bitcoin, which was up 13% over two days.
Deutsche Bank strategist George Saravelos compared the effect to the Fed's 2011-12 Operation Twist, which flattened the yield curve measuring the gap between short-term and long-term yields by selling short-dated debt and buying long-dated securities. The buybacks, along with encouraging foreign central banks to use a Fed repo facility rather than sell Treasuries outright, are "soft-form financial repression" to hold down longer-dated yields, he said.
Not everyone sees this as a decisive shift. Sarah Ying, head of FX strategy at CIBC Capital Markets, called it a "mini" version of past dollar-stress episodes — milder than April 2025's "Liberation Day" selloff or January's pressure. It looks less like markets testing Washington's resolve than the reverse, she said. "It's really Bessent testing the market, and then the market fighting back."
POLITICAL TIMING RAISES QUESTIONS
The timing has fueled political speculation, too. With midterms approaching, lower long-term yields, especially mortgage rates, would help the Trump administration politically. "Gasoline prices are still high, mortgage rates are rising, which with the midterms just around the corner may be something that they want to address," Osborne said.
Still, Treasury's room to maneuver is limited. Pushing too hard to ease conditions risks reigniting inflation and forcing a more hawkish Fed. "Fed hikes into midterms don't seem like the greatest story in the world," said Ying.
Steve Englander, global head of G10 FX research and North American macro strategy at Standard Chartered Bank, argued that what unsettled investors is less the fiscal math than the sense that Bessent is improvising through interventions in illiquid market corners — tactics that can look like "a panic response" and lose credibility if overused.
"He really caught us looking the wrong way twice already," Englander said, but he expects the dollar will be ultimately supported by relatively high yields and economic fundamentals, including strong U.S. productivity and earnings growth.
The episode changes neither side of the ledger, Englander said. "It's not going to change the good fundamental, which is the productivity side of the economy. It's not going to change the bad fundamental, which is the deficit side."
(Reporting by Karen Brettell in New York; Editing by Colin Barr and Matthew Lewis)
