UBS Financial Services Inc. must face a proposed class action challenging its rates on uninvested cash that gets transferred to interest-bearing deposit accounts as part of its cash sweep program.

A pair of UBS customers plausibly alleged that the investment adviser breached its contract with them by failing to base interest rates on prevailing business and economic conditions, the US District Court for the Southern District of New York said Wednesday.

The “exceedingly broad” definition of the term “agreement” in UBS’ agreements with Andrew Davitt and Kelly Goldsmith includes all documents the firm makes available to the plaintiffs, Judge …