U.S. securities regulators plan to penalize Morgan Stanley 6.1 million U.S. dollars for allegedly overcharging customers on 59 million dollars in bond sales, The Wall Street Journal reported on Thursday.

Morgan Stanley allegedly overcharged customers of its retail brokerage unit in more than 2,800 separate bond sales from the firm's own inventory, the report quoted people familiar with the case as saying.

The securities regulators plan to fine the blue-chip securities firm 1.5 million dollars and order 4.6 million dollars in restitution to customers who paid markups as high as 18 percent in2001 for surplus notes issued by Kemper Lumbermens Mutual Casualty Co., according to the report.

The case shows how difficult it can be for individual investors to know what price they should be paying for individual bonds -- unlike stocks or mutual funds whose current market prices are widely disseminated, said the report.