Kim Kardashian, Sugar Ray Leonard, Britney Spears, Ringo Starr.When it comes to choosing spokespeople to endorse its brightlycolored footwear, Skechers U.S.A. Inc. has gone for a diverselineup of celebrities.

But when it comes to picking who sits on the board of theManhattan Beach, Calif.-based company, things look decidedly moremonochrome: nine white men, the youngest of whom is 48 yearsold.

That homogeneity rankles an increasing number of investors, whoare demanding that boards become more diverse. In fact,shareholders have been so successful in pressing the largest U.S.companies to add women to their boards, they're now drilling downinto the next tier of businesses and shining a spotlight ondiversity—or rather the lack of it—at midcap and smaller members ofthe Russell 3000 Index such as Skechers.