Student-loan servicer Navient Corp has rejected a $3.2 billion takeover bid from two investors, a source familiar with the matter told Reuters.

Navient's board voted on Monday to reject the $12.50 per share offer from hedge fund Canyon Capital Advisors and private-equity firm Platinum Equity Advisors, believing it undervalues the company, according to the source.

The offer represents a 6.6 percent premium over Navient's Friday closing price of $11.73 a share.

Navient's advisers had told Canyon it would require a price of more than $15, the Wall Street Journal reported on Monday, citing people familiar with the matter.