Morgan Stanley is expected to pay $6.1 million to securities regulators to settle charges that it overcharged retail customers for bond sales, according to the Wall Street Journal.

The bank allegedly overpriced bonds in more than 2,800 separate sales from its retail brokerage unit.

The Financial Industry Regulatory Authority, which began operations on Monday after the merger between the regulatory arms of the N.A.S.D. and the New York Stock Exchange, levied the fine. The agency also plans to charge Kenneth Carberry, the Morgan Stanley corporate bond trader who allegedly set the excessive prices.

Retail investors are often in the dark about how much they are paying for bond investments. The fees come in the form of markups to the bond prices, so it's not as easy to determine costs as it is from stock-trade commissions.

The bonds at issue at Morgan Stanley were sold from its own inventory. The firm sold corporate bonds to small investors at prices between $98.50 and $103, while its own trading positions on the same securities showed prices between $88.22 and $93.23.

The markups would have been between 6 percent and 16 percent. Any markup over 5 percent may violate guidelines.