Green’s Dictionary of Slang

to use one’s money to back an enterprise, esp. a theatrical production.

1929		W. Winchell On Broadway 1 Oct. [synd. col.] The show ‘Divided Honors’ is angeled by James Imbrie, of Wall Street.
1938		W. Winchell ‘On Broadway’ 26 Dec. [synd. col.] The Great White Father in Washington who angels more shows than even Jock Whitney.
1948		Lait & Mortimer N.Y.: Confidential (1951) 194: A revue angeled by gangster dough.