Princeton University has become the fourth Ivy League school to refrain from making additional investments in HEI Hotels & Resorts.

The decision, which the Daily Princetonian confirmed with Princeton Investment Company President Andrew Golden on Wednesday, follows Yale’s announcement last fall that the University will not invest in a fourth fund by the company. The National Labor Relations Board has investigated HEI over complaints of illegal retaliatory behavior in labor relations.

Nigel Hurst, senior vice president of human resources for HEI, told the News in November that a Yale representative informed him the University’s decision was motivated by “purely portfolio reasons.” Similarly, Golden said Princeton’s decision was “based purely on business reasons.”

“It would be absolutely wrong to infer that [the Princeton University Investment Company] had concluded that HEI was out of compliance with regulations or industry standards,” Golden said.

HEI first came under fire in fall 2008 when students at universities across the country decried its alleged mistreatment of workers and interference in workers’ efforts to unionize. Brown University decided to halt future investments in HEI on the recommendation of its investments responsibility committee in February 2010. The University of Pennsylvania, which only invested in the company’s first fund, announced in March 2010 it had no plans for future investments with HEI.