Premise: Mickey's Birthday Party is a theatrical cartoon short made by Walt Disney and distributed by RKO Radio Pictures. It was released on February 7, 1942. The animated film was directed by Riley Thomson and animated by Les Clark, James Moore, Ken Muse, Armin Shaffair, Riley Thompson, Bernie Wolf, and Marvin Woodward.
Hypothesis: RKO Radio Pictures distributed and made a fortune from the hit cartoon Mickey's Birthday Party