The all-important spring housing market is off and running, and while the pace isn’t expected to be strong, there are signs of optimism, at least among sellers. Some who gave up last year are jumping back in.

Nearly 45,000 homes that were delisted last year were relisted for sale in January, according to Redfin, a real estate brokerage. That is the highest January figure since Redfin began tracking this metric a decade ago and represents a record 3.6% of homes that were on the market in January.

The January figures come as Redfin reported a record number of sellers pulling their homes off the market last September. Close to 85,000 sellers delisted, up 28% from September 2024. Higher mortgage rates last year, still-high home prices and growing uncertainty in the economy sidelined buyers last fall, taking sellers out of the driver’s seat, where they had been in the years during and just after the pandemic.

Ashley Rummage, a real estate agent in Raleigh, North Carolina, in response to CNBC’s fourth-quarter Housing Market Survey, said in December that more sellers were being asked for concessions, and some just refused.

“A lot of sellers I’ve encountered and worked with have just thrown their hands up in the air and said, ‘If we can’t get what we want for our house right now, or what we think is it’s worth, then we’re gonna go ahead and take it off to market and try again, maybe in the spring,’” Rummage said.

The overall inventory of homes for sale nationally is higher than it was a year ago, but the gains are plateauing, according to Realtor.com. Active listings were up 7.9% in February, year-over-year, but that number has been shrinking for nine straight months. Listings are still down 17% from 2019, pre-pandemic.

“Inventory has improved for more than two years, but the momentum has faltered in recent months,” said Danielle Hale, chief economist, Realtor.com. “Supply gains have been concentrated in the South and West and skewed toward homes priced below $500,000. While the Northeast and Midwest have seen growth, they remain significantly undersupplied.”

With rates now hovering near four-year lows, Hale said, a key question is whether this “thaw” spurs more buyers or more sellers. Mortgage rates have climbed slightly higher in recent days, due to the ongoing war with Iran and renewed fears over inflation.

The online mortgage platform Better has partnered with OpenAI to launch an app within ChatGPT that the companies said will dramatically reduce the time it takes to underwrite a mortgage or home equity loan, CNBC has learned exclusively.

The app, to be announced later Thursday, takes Better’s mortgage engine and combines it with OpenAI’s models to speed up the underwriting process for loan officers working at banks, mortgage brokers and fintech firms, Better CEO Vishal Garg said in an interview.

“Taking the mortgage underwriting process, which so many of us have experienced personally, from 21 days to as little as 47 seconds and enabling it via ChatGPT is a huge unlock for everyone,” Giancarlo Lionetti, OpenAI’s chief commercial officer, said in a statement provided to CNBC. “OpenAI is proud to partner with Better to build technology that revolutionizes the mortgage industry and makes it cheaper, faster, and easier for American families to finance a home.”

For decades, creating a mortgage has been one of the most time-consuming corners of American finance, with lenders relying on dozens of steps that can take weeks to complete. After the 2008 financial crisis, big banks like JPMorgan Chase receded from the U.S. mortgage market, leading to the rise of non-bank players including Rocket Mortgage and United Wholesale Mortgage.

Now, in an era where the leading artificial intelligence firms are targeting inefficiencies across the corporate landscape, it’s possible that AI agents could reshape a U.S. home-loan market that originates more than $1 trillion in mortgages a year.

Garg said the new app is part of Better’s pivot from being primarily a lender to consumers to also becoming a “mortgage-as-a-service” tech platform for other mortgage players.

The companies are taking direct aim at the dominant mortgage players by enabling competitors to move faster, Garg said. According to Better, lenders can save 21 days of time on average, reducing the costs to underwrite loans and ultimately saving consumers money as well.

“AI is now doing mortgages,” Garg said. “Rocket, UWM, Pennymac, a bunch of guys that are large public companies, make their money by effectively charging a tax of one and half percent to underwrite mortgages. … That’s $20 billion that’s paid by the American public in a typical year.”

OpenAI’s models, fed with Better’s mortgage data, save time by simultaneously running parallel workflows on dozens of checkpoints, including appraisals, title reports, income, credit reports and other metrics, Garg said.

“It’s not a simple tool call. It’s a multiple tool call with a super long, extended logic tree and a very large context window,” Garg said.