It wasn’t supposed to be this way.

Realtors, mortgage brokers, and economists anticipated a busy fall homebuying season as inventory improved and buyers — buoyed by the Federal Reserve’s jumbo interest rate cut — came off the sidelines to take advantage of mortgage rates at a two-year low.

But after a vanishingly brief honeymoon period, rates started rising. They’ve been up for five weeks straight and, in recent days, have trended north of 7%, a level that some market watchers say will keep potential buyers sidelined. Housing contract activity showed signs of life in September when mortgage rates were lower, but home sales this year are on track to hit a multi-decade low.

A combination of factors has pushed up mortgage rates quickly. Treasury yields, which mortgage rates follow closely, have risen dramatically in recent weeks in the face of strong economic data and pre-election jitters. Economic uncertainty surrounding next week’s election may complicate their path back down.

“This run-up in mortgage rates over the last couple of weeks has probably been very surprising for Fed officials,” said Chen Zhao, who leads Redfin’s economics research team. “I think it’s been surprising for everyone.”

The Fed doesn’t directly control mortgage rates. Instead, rates move primarily based on expectations about the direction of interest rates in the future. Last month, a string of hot economic data on almost everything from consumer spending, inflation, wages, and hiring called into question how much further the Fed would need to ease interest rates to support the economy in the months ahead.

In other words, all those positive signs for the economy are notches in the negative column for interest rates — including home loans — coming down.

Read more: How the Federal Reserve rate decision affects mortgage rates

At the same time, Treasury yields began a dramatic rise as traders began pricing in a possible election victory for former president Donald Trump, whose proposed policies of tariffs and tax cuts are seen as bad for bonds — tariffs are generally inflationary, which would require higher interest rates, while tax cuts would likely require the US to issue more debt. That can drive up interest rates if there isn’t more demand to meet the increased supply.

Economic data released this week muddied the picture further. Treasury yields briefly fell on Friday morning in response to a lackluster jobs report, raising the possibility that mortgage rates would move downward in response. But the reaction was short-lived. By mid-morning, they were higher again.