Harvard's substantial interests in a company that invests primarily in gambling are unethical, the Progressive Student Labor Movement wrote in a letter delivered to the Harvard Corporation on Friday.

Harvard has invested at least half a billion dollars in Highfields Capital Management, one of the largest stockholders of Las Vegas casino owner Park Place Entertainment.

In Friday's letter, PSLM asked the Corporation to divest Harvard from Highfields Capital because of its stake in the gambling industry.

"For the sake of public perception and to fulfill its ethical mission as an institution of human learning, Harvard must reevaluate its relationship with Highfields Capital," the letter reads.

The request comes after months of research spearheaded by PSLM member Aaron D. Bartley, a third-year student at Harvard Law School.

He said he stumbled across Harvard's relationship with Highfields while researching the University's investments on the Internet.

"I was pretty surprised," Bartley said.

Bartley said that the investment is particularly objectionable since Highfields' history and management are so closely linked to Harvard.