A listing could come as soon as November, one of the people said. Unison and its competitors have originated more than $2.6 billion in financings this year through Sept. 30, up about 30% from the same period last year, according to data from SFR Analytics.

I read that 30% jump as real demand from homeowners who can't or won't take on more monthly debt. But here's the part that keeps me up: the product itself.

Instead of monthly payments, consumers write one check to Unison when they sell or refinance their home. The agreements appeal to homeowners who can't qualify for a traditional home-equity loan, or don't want to add to monthly interest payments from mortgages, credit cards or car loans. Critics warn that the products can be difficult for consumers to understand, and in some cases, punishingly expensive.

Unison was founded in the early 2000s by Thomas Sponholtz, who was looking for a way to give institutional investors exposure to US home price appreciation. Demand didn't grow meaningfully until after the US foreclosure crisis, when competitors such as Point, Hometap and Splitero entered the market.