Moody's Corp.'s first-quarter earnings rose 8.6% as the ratings company continued to benefit from strong bond issuance. 

In a high-profile case, Moody's agreed to pay $75 million to settle lawsuits alleging the ratings firm — along with Standard & Poor's Ratings Services and Morgan Stanley. 

Moody's Investors Service, the company's ratings business and its biggest top-line contributor, generates more revenue from corporate finance than from any other type of finance. For the latest period, the business posted a 15% increase in revenue to $521.2 million.