Lens Investment Management of Portland, Maine filed a preliminary proxy statement Feb. 23 asking investors to force a sale of Pioneer Group of Boston, claiming that the firm's non-U.S. ventures have distracted the firm from its core focus.

The proxy also seeks a vote on a slate of four Lens officers to serve on the board of directors of the company.

Pioneer "has diluted [Lens'] human and financial capital by expanding into operations of unrelated businesses that are far removed from its core expertise and located on four continents. The company's international mistakes have generated a staggering $194 million in net losses since 1997. We believe that something is broken at Pioneer that your current management and board of directors cannot fix," the proxy said.

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