U.S. Long Bond Yields Surge as the U.S. Treasury Expands Buybacks: Where Fixed Rates Go Amid a Bear Steepening

Published Thursday, August 20, 2026 · Rates, market figures and outlooks in this article reflect its publication date and may differ today. Ask us for the latest picture. Translated from the Korean original.

U.S. 20- and 30-year long-term Treasury yields have recently climbed steeply, and a "bear steepening"—in which the gap between short- and long-term rates widens—is now in full swing. With long-term market rates surging on their own, independent of short-term policy rates, direct upward pressure is being placed on Canadian 5-year fixed mortgage rates, which are closely linked to U.S. Treasuries. In response, the U.S. Treasury has stepped in with emergency measures, doubling its limit for repurchasing (buying back) long-term bonds.

Key Points

• Bear steepening intensifies: Ultra-long Treasury yields such as the 20- and 30-year are rising faster than short-term rates, steepening the yield curve in a continuing bond sell-off.
• A triple squeeze on the bond market: The snowballing U.S. fiscal deficit, reduced buying of long-term U.S. Treasuries by foreign central banks (Japan, China) and Middle Eastern countries, and massive investment-grade corporate bond issuance by Big Tech hyperscalers to fund AI infrastructure have combined to seriously shake supply and demand for long-term U.S. Treasuries.
• U.S. Treasury doubles its long-bond buyback limit: To prevent a liquidity crunch in the bond market and a spike in long-term rates, the U.S. Treasury abruptly doubled its long-term Treasury repurchase (buyback) limit, stepping in directly as the market's "buyer of last resort."
• Multiple lines of defence for long-term rates: Joint U.S.–Japan yen intervention and the Fed's Treasury-collateralized lending (FIMA repo), now joined by the Treasury's expanded buybacks, have formed a shield against an extreme spike in long-term yields.
• Impact on Canadian fixed rates: These emergency measures have, for now, calmed the bond market panic and the surge in the Government of Canada 5-year bond yield (GoC 5Y), but structural supply pressure means fixed mortgage rates remain strongly resistant to falling.

What It Means

The U.S. Treasury's decision to double its long-bond buyback limit clearly shows how seriously the U.S. government views the current bear steepening in the bond market as a systemic crisis. By directly buying illiquid long-term Treasuries to give the market breathing room, the U.S. government is, for now, effectively preventing the feared uncontrollable global rate spike and financial market tantrum.

However, the government's artificial bond purchases are only a buffer to put out the immediate fire; they cannot quickly resolve the fundamental supply burden of snowballing fiscal deficits and hyperscalers' bond issuance for AI infrastructure. So even if the short-term panic has calmed, it is too early to expect Canadian fixed mortgage rates to turn into a steep decline. If you are planning an upcoming mortgage renewal or a new home purchase, we recommend that, given market volatility, you carefully review your household cash flow and debt-repayment plan by a conservative yardstick rather than counting on the illusion of a sharp rate drop.