Does unified party control of government steepen the yield curve?
Core argument: The US yield curve often steepens when one party gains unified control of government, as in late 2016 with Trump and GOP majorities in the Senate and House, and again in early 2021 with a Democratic sweep.
The yield curve often steepens when control of the US government shifts from two parties to one, as seen in late 2016 when President Trump and the GOP controlled both the Senate and House. This pattern recurred in early 2021 with a Democratic sweep, leading to expectations of a fiscal-heavy agenda and higher long-end yields. Historical data shows bond yields rise with increased party confidence, as measured by the Michigan survey of consumers. Conversely, yields tend to fall when a party loses control, such as when the GOP lost Congress in late 2018. This dynamic reflects global investors' response to political risk and fiscal policy changes, suggesting that further yield increases could occur if Democrats pursue aggressive fiscal measures.




Ed Comment: “It’s the FDR effect—each side goes nuts without the other side to rein them in.”
Tracy Alloway looks at US Federal election’s impact on yields, "...on a longer-term chart the move lower in U.S. Treasury yields doesn’t look so odd. In fact, it’s the sharp upwards move that starts to look weird. As Joe mentioned before, the move upwards that took place between the U.S. presidential election in November and early in the Spring coincided with a Democratic sweep of Georgia and the flipping of the Senate into Democratic control. That set off a ton of speculation that Democrats would push through a fiscal-heavy agenda — all while the Federal Reserve kept policy relatively easy, which contributed to expectations for higher growth and more inflation and therefore higher yields at the long-end.... the yield curve has a history of steepening as control of the U.S. government shifts from two parties to one party. That’s exactly what happened in late 2016, when President Donald Trump won the presidency with Republicans in control of both the Senate and the House of Representatives. You can see the dynamic from the (rough) chart below, which shows bond yields moving up when there’s a big spike in Republican or Democrat confidence, according to the Michigan survey of consumers (which I’ve used as a proxy for the parties securing greater control). Of course, the opposite move can also happen when a party loses control — with bond yields heading lower after the GOP lost control of Congress in late 2018...."