Wells Fargo employees improperly altered or added information on documents related to corporate customers last year and early this year as it was trying to comply with a regulatory consent order over anti-money laundering controls, The Wall Street Journal reported Thursday.

The report, citing people familiar with the matter, said employees in the wholesale division added or altered the information without customers' knowledge, including Social Security numbers, addresses and dates of birth.

The bank became aware of the behavior in recent months from employees, the Journal reported. The bank is still investigating the matter and has reported the behavior to the Office of the Comptroller of the Currency, which is probing the issue, the newspaper said.

Shares of Wells fell 1.4 percent Thursday.