One of the odder distortions created by post-crisis financial regulation—the unprecedented decline in U.S. swap rates below Treasury yields—may be poised to end.

Swap rates, what companies pay to exchange fixed interest payments for floating ones, are on track to rise back above Treasury yields across all maturities for the first time since 2014. The swap spread, as the gap between the two is known, turned negative in 2008 at the long end for the first time ever. It was the start of a shift that traders view as anomalous because it theoretically indicates that the market views the credit of banks as stronger than that of the U.S. government.

Now several forces are at work that are restoring the relationship to what it was in the decades before the financial crisis—including the prospect that Republicans' tax overhaul plans could reduce corporate issuance, stemming the typical post-sale use of swaps. There's also speculation that regulatory relief is ahead for banks, making it more attractive for them to hold Treasuries.