Citigroup Inc. is testing a Web site intended to help the children of wealthy people manage their allowances and to alert parents and bankers when the children blow through their cash too quickly.

The site was developed by Tile Financial LLC, which was founded by former New York Stock Exchange finance chief and Bear Stearns Cos. analyst Amy Butte.

Banks are trying to nurture relationships with clients' children to ensure fortunes are not transferred to other financial advisers as wealth shifts to the next generation, Butte said in an interview.

The New York banking company made a minority equity investment in Tile last week, said Chris Kay, head of Citigroup's growth ventures and innovation unit. He declined to disclose the size of the investment. The test began in June.

"Inter-generational wealth transfer is a very big issue for the industry," Butte said, because $1 trillion is to be inherited in the U.S. through 2025. "Even if we're half wrong, it's still hundreds of billions of dollars."

The Tile portal, called Spend Grow Give, is available to clients of Citigroup's private bank, which caters to people with more than $25 million, including one-third of the world's billionaires.

Young heirs can get spending accounts linked to debit cards, and they can build investment portfolios in consultation with a parent's private banker.

Tile also offers one-click giving to several preapproved charitable organizations.

The vendor plans to introduce electronic alerts that will be sent to parents if their child spends an allowance too early in the month, Butte said.

Tile typically charges users an annual $150 subscription fee, Butte said, declining to specify how much Citigroup is paying.