Edward Jay Epstein tells you "How To Finance a Hollywood Blockbuster" in this Slate article.
"As paradoxical and absurd as it sounds, it's cheaper for a Hollywood studio to make a big-budget action movie than to make a shoestring art film like Sideways. Consider Paramount's 2001 action flick Lara Croft: Tomb Raider. On paper, Tomb Raider's budget was $94 million. In fact, the entire movie cost Paramount less than $7 million."