Broadway is booming, and now more actors are going to share in the riches.

In a groundbreaking agreement Friday, the commercial producers who finance Broadway’s big hits have agreed to give a percentage of profits to performers who help develop successful shows.

The deal, reached between Actors’ Equity, a union representing 51,000 performers and stage managers, and the Broadway League, a trade organization for producers, is a milestone, marking the first time that the industry’s financiers have tacitly agreed to acknowledge that performers are contributing ideas, not just labor, to shaping new musicals and plays.

Hit shows already generate paydays for producers, directors and stars; many of them now will bring steady if modest paychecks to the supporting actors and dancers, some of whom still take survival jobs, like waiting tables, between shows.

“Creating a new show is hard,” said Mary McColl, the union’s executive director. “If we’re along for that ride at the beginning, for not much money, we think we should be able to share in the success once it has recouped its expenses.”