In the latest in a string of high-profile data disclosures, the brokerage services group of ADP (Automatic Data Processing) last week said "an unauthorized party impersonated officers" at an undisclosed number of public companies to obtain investor information between November 2005 and February 2006.
The company, based in Roseland, N.J., did not say how many companies or investors were affected.
ADPs brokerage services division provides transaction-processing and investor communication services to financial firms.
According to The Wall Street Journal, Fidelity Investments said 125,000 of its customers were among those whose information was breached; UBS said 10,000 of its customers were affected, and Morgan Stanley said about 3,800 of its customers were involved.
In a statement sent to Baseline, ADP noted that the information included only investors names, addresses and the number of shares of stock held in their accounts.