According to Forbes, Portman topped the list of best actors for the buck, bringing in about $42.70 for every dollar she earns.
"Compare that to Eddie Murphy, our most overpaid star, who returns $2.30 for every dollar he gets paid," Forbes.com explained, noting that Portman "doesn't demand a giant payday (yet), she's a fantastic investment."
Take her 2010 film, "Black Swan," for example. It cost an estimated $13 million to make, but grossed a whopping $329 million at the box office worldwide, reports Forbes.
Forbes' second most bankable star was Stewart. The actress, who also leads the magazine's 2012 list of highest-earning actresses, rakes in $40.60 for every dollar she makes.
Other "Twilight" stars made the list, too, including Robert Pattinson, who came in at fourth and Taylor Lautner in sixth place.
Take a look at the complete list here.