Morgan Stanley may have its long-term credit rating cut by Moody's Investors Service, the ratings agency said on Friday.

Moody's is evaluating the company's Aa3 credit rating as the securities firm endures lower earnings in the midst of faltering mortgage and credit markets.

Since the onset of the credit crisis one year ago, Morgan Stanley's financial performance and risk management has been inconsistent, and below the levels expected of a Aa3-rated financial institution,'' Moody's said on Friday in a statement.

Last week, Morgan Stanley said earnings for its second quarter were down 57 percent. Its shares have fallen more than 30 percent this year.

Earlier this month, ratings agency Standard & Poor's cut Morgan Stanley's credit rating citing similar concerns. Moody's will look closely at Morgan Stanley's risk controls and earnings in the next one to two years.