S&P Global Ratings lowered its long-term issuer credit rating on Navient Corp. to BB- from BB.

The rating agency also lowered its senior unsecured debt rating on Navient to B+ from BB- and affirmed its B short-term issuer credit rating.

The outlook is negative.

The possible magnitude of the Consumer Financial Protection Bureau's recent complaint against Navient and certain units increases the risk profile of the company, according to S&P credit analyst Matthew Carroll. The litigation's outcome is not certain, but if the lawsuit succeeds, S&P believes it could result in a substantial financial impact to the company.

The outlook is based on the risks S&P sees resulting from the litigation and the company's concentration of large unsecured debt maturities in 2018 to 2020.

S&P Global Ratings and S&P Global Market Intelligence are owned by S&P Global Inc.