The financial magazine's Web site gives the actor a score of 10 out of 10 for his bankability in its first "star currency" list, compiled by surveying more than 150 industry professionals.
Following Smith on the list: Angelina Jolie, Brad Pitt, Johnny Depp and Leonardo DiCaprio, who all tied for second with a score of 9.89. Tom Hanks, George Clooney, Denzel Washington, Matt Damon and Jack Nicholson rounded out the top 10.
Smith's superior box-office clout has been long established. He's known for "owning" the July Fourth weekend box office with films such as "Independence Day" and "Men in Black," and has had few flops.
The 40-year-old actor recently topped the annual poll by Quigley Publishing Co., which has surveyed movie exhibitors since 1932 on which stars generate the most box-office revenue.
The Forbes survey, which acknowledged that it was "subjective," also took into account a star's ability to attract financing for a project. The list was released Tuesday.
Smith's latest film, "Seven Pounds," received terrible reviews, but still earned $70 million at the domestic box office. His summer superhero blockbuster "Hancock" grossed $228 million.
What the El!?! Editorial:
I finally saw Hancock, and I sorta liked it. I can see why Will is bankable. He brings in the box office and the DVD rentals and sales.