If you're making a film and want the most bang for your buck, give Natalie Portman and Kristen Stewart a call. (We know a certain director who already picked up on this tip with K-Stew, though...)

The two leading ladies are among the most highly paid actresses in Hollywood, but there's a good reason for that: they have the best track record in making money. Forbes looked at the last three films that actors have starred in over the last three years, calculating the return on investment for the studios who pay their salary. Natalie topped the list, returning studios $42.70 for every dollar she's paid. Compare that to Eddie Murphy, the most overpaid star on their list, who returns a paltry $2.30 for every dollar he's paid.

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Part of the reason Natalie topped the list is because her films make big salaries with relatively small budgets. Black Swan grossed $329 million worldwide on a $13 million budget, while No Strings Attached made $150 million on a $25 million budget. Although the studio that produced Your Highness ended up losing $25 million, she was still the clear winner.

Kristen demands a far higher salary than Natalie, but has proven worth the investment. She was paid $25 million to star in the last two Twilight films, but the franchise has grossed over $3.3 billion at the box office. She ultimately returns $40.60 for every dollar paid.

Rounding out the top 5 are Shia LaBeouf ($35.80), Robert Pattinson ($31.70) and Daniel Radcliffe ($30.50).

What do you think of Natalie being Hollywood's most bankable star?

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