An Israel-based firm has amassed a sizable stake in the corporate bonds of Florida’s Brightline rail project and is gearing up for workout talks, as the cash-strapped venture struggles under its debt pile.

An entity of Phoenix Financial Ltd. that holds nearly 10% of the debt has retained law firm Glenn Agre Bergman & Fuentes for advice, according to people familiar with the matter who asked not to be identified discussing private information. Brightline has roughly $1.1 billion in corporate bonds, according to data compiled by Bloomberg.