Because of a systems glitch, incorrect ratings were assigned to about 300 of the 3,000 stocks offered through Charles Schwab Corp, The Wall Street Journal reports.

At about 6 p.m. Pacific time this past Sunday the errors occurred, and were corrected Monday at 11 a.m., at which time Schwab posted an urgent message on its website, making customers aware of what happened.

Schwab says that it will reverse any trades that customers made as a result of the ratings, at no cost. Approximately 3,100 trades were affected.

The mistakes had no impact on the Schwab mutual funds.

This is the first time that anything like this has ever occurred at Schwab.

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