The Federal Reserve cut its benchmark interest rate to 0% on Sunday — but don’t necessarily expect lower mortgage rates as a result.

The Fed announced it would cut interest rates a full percentage point Sunday night, in addition to a $700 billion quantitative easing program.

The central bank had already made the rare move to lower the federal funds rate by a half-point two weeks ago to a range of 1% to 1.25% in between its regularly scheduled meetings. In both cases, the Fed noted that the move was in response to the risks the COVID-19 coronavirus outbreak poses to the economy.

The novel coronavirus first emerged around Wuhan, China, late last year. As of Sunday, there were nearly 160,000 confirmed cases worldwide and around 6,000 deaths.

When the Fed cut interest rates two weeks ago, mortgage experts noted that the central bank was “catching up” to where markets had headed. “Mortgages respond to market forces and not to the Fed,” Holden Lewis, mortgage and real estate expert at NerdWallet, told MarketWatch earlier this month. “The Fed is actually following and not leading when it comes to mortgage rates.”

Also see: As mortgage rates remain near three-year lows, here are 5 questions to ask yourself before you refinance your mortgage

Mortgage rates have plummeted since the beginning of the year to the lowest average in 50 years as a result of market movements in response to the coronavirus. While the Federal Reserve adjusts short-term interest rates, mortgage rates fluctuate based on long-term bond rates.

In particular, mortgage rates in the U.S. roughly track the direction of the yield on the 10-year Treasury note TMUBMUSD10Y, 0.701% . The 10-year Treasury had fallen to all-time lows in recent weeks as investors fled to the safety of bond markets amid the downturn in equity markets.

Continued downward movement in the 10-year Treasury would normally signal downward movement in mortgage rates. Where they stand now, Treasury yields suggest that mortgage rates still have some room to move lower, said Rick Sharga, a mortgage industry veteran and president and CEO of CJ Patrick Company, a financial-services consulting firm. “I wouldn’t be surprised to see 30-year loans with 3.0% rates before things settle back down,” Sharga said.

But another question is emerging in the current low rate environment: Will lenders let mortgage rates go lower?

“ ‘A big question now becomes what kind of capacity lenders have.’ ” — —Tendayi Kapfidze, chief economist at LendingTree

“A big question now becomes what kind of capacity lenders have,” said Tendayi Kapfidze, chief economist at LendingTree TREE, -3.39% . “If you don’t have enough people to process the volume you’re getting in, you’re not going to lower rates to attract more volume.”

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Current low rates have already caused a boom in refinance activity. And demand among home-buyers remains elevated, in spite of the short supply of homes for sale. As a result, lenders don’t need to give Americans much more incentive to apply for new home loans.

Last week, mortgage rates actually increased slightly, in part because some lenders had artificially raised rates to stem the number of people applying for home loans and give themselves time to work through the backlog of applications that accumulated as rates fell. Lenders will also face pressure to hedge with interest rates, since bond yields could increase from the time when a borrower locks in a rate until when they close the loan, which would make it harder to sell the loan on the secondary market.

Those in the refinance market would be smart to lock in rates now, Kapfidze said. “Most lenders will let you relock at the lower rate” when you close the loan, he said.

One exception to the mortgage rates trend could be home equity lines of credit, or HELOCs. These are adjustable-rate loans based on the prime rate. As such, they are set to see a drop in interest rates, since the prime rate does closely follow the Fed’s benchmark federal funds rate.

“HELOCs have been slowly falling in popularity, and over time the amount of HELOC debt has been gradually falling as people pay down their debts and fewer people take up the slack by borrowing them,” Lewis said. “This seems time for that trend to possibly reverse. The rates on HELOCs are going to be so tempting, especially for people who want to fix up their homes.”

This story was updated on March 15, 2020.