One of the leanest housing markets in history might be putting on some fat. The supply of homes for sale could increase in the next few weeks, according to new data from Realtor.com.

In April, inventory was 12% lower than in the same month last year, the smallest year-over-year decline since the end of 2019. Another reading for just the last week in April shows inventory down only about 3% from a year ago.

“April data suggests a positive turn of events is on the horizon for weary buyers: If the trends we’re seeing now hold true, we could potentially see year-over-year inventory growth within the next few weeks,” said Danielle Hale, chief economist for Realtor.com.

The shift in supply is likely due to a slower sales pace stemming from the recent rapid increase in mortgage rates, which has made expensive homes even pricier. The average rate on the 30-year fixed has jumped more than 2.5 percentage points since the start of the year.

New listings were down 0.9% in April compared with a year ago, and the number of active listings is still down 67% from pre-pandemic levels. The growth in supply is being led by mid-sized family homes, as fewer are going under contract despite it being the spring market, a popular time for families to shop for houses.

Higher mortgage rates, combined with record high home prices, have sidelined much of the competition. Home prices are up about 34% since the start of the pandemic. The monthly mortgage payment on a $400,000 home, with a 20% down payment, is now $467 more than it was in March 2020, according to Realtor.com.

These factors are translating into fewer potential buyers and a slowdown in bidding wars.

“Sanity seems to be returning,” said Paul Legere, a buyer agent with Joel Nelson Group in Washington, D.C. He said the lender with whom he works says one in four potential mortgage borrowers have been knocked out of the market due to higher rates.

“The 25% reduction in buyers gets us to some sort of reasonableness, but it is still tough for less-than-strong buyers,” said Legere. He said the million-dollar market is still “brisk.”

The typical home spent just 34 days on the market, six days fewer than a year ago, which beat the previous record low of 36 days in June 2021, according to Realtor.com. Homes sold at the fastest year-over-year pace in the following markets: Miami, St. Louis, Raleigh, Orlando and Hartford.  

While not one of the fastest-moving markets, offers are still strong in the Boston area, even in the luxury sector, said real estate agent Dana Bull of Sotheby’s International Realty.

“Prices haven’t cooled yet, but some sellers have unrealistic expectations around price. Some hard conversations are being had prior to listing to set expectations with sellers,” said Bull. “Although inventory is on the rise, buyers are still coming out of the woodwork and committed to landing homes, so new inventory and new demand seem to be increasing in lockstep.” 

The key to inventory growth will be fewer buyers and more sellers, but the affordability conditions don’t exactly favor that. Homes are now less affordable in 95% of U.S. housing markets compared with their historical averages, according to recent calculations by Black Knight, a mortgage technology and data provider.

Another survey by Gallup found about 70% of Americans say now is a bad time to buy a home. That is the highest share since the polling organization began asking the question back in 1978.

“The next eight or so weeks are going to be crucial for buyers and sellers as this is crunch time,” Bull said. “Buyers want to secure homes right now, and sellers want to capitalize on peak demand.”