Morgan Stanley will pay a $1 million fine and compensate harmed investors to settle civil charges that the bank failed to give customers the best market prices for some corporate and municipal bonds, U.S. brokerage regulators said on Thursday.

The Financial Industry Regulatory Authority said Morgan Stanley Smith Barney LLC and Morgan Stanley & Co would pay the fine plus roughly $188,000 in restitution for the various pricing violations, which occurred between January 2008 through September 2011.

The bank agreed to settle the case without admitting or denying the charges by FINRA, which self-polices the brokerage industry.

Morgan Stanley spokesman James Wiggins said the company had cooperated with FINRA's investigation.

"The settlement involved fewer than 300 fixed income transactions over a four-year period during which some 4 million such trades were conducted," Wiggins said. "FINRA did not allege any willful or fraudulent conduct by the firm."

According to FINRA, Morgan Stanley failed to use "reasonable diligence" to ensure that prices were fair under current market conditions in 116 corporate bond transactions.

In addition, FINRA said it found that the bank did not reasonably price 165 different municipal bond trades.

"Firms must ensure that customers who buy and sell securities - including corporate, agency, and municipal bonds - receive execution prices that are consistent with prices available in the marketplace," said Thomas Gira, the executive vice president for FINRA Market Regulation.