FILE PHOTO: A sign is displayed on the Morgan Stanley building in New York U.S., July 16, 2018. REUTERS/Lucas Jackson/File Photo

(Reuters) - Morgan Stanley MS.N has fired or placed on leave at least four traders over alleged mismarking of securities that concealed losses of between $100 million and $140 million, Bloomberg reported on Thursday citing people familiar with the matter.

The company is investigating the suspected mismarking that was linked to emerging-market currencies and the traders were based in London and New York, according to the report. (bloom.bg/33wcdRI)

A Morgan Stanley spokesman declined to comment on the report. The probe at the sixth largest U.S. bank relates to complex trading products including so-called FX options that give buyers the right to trade currencies at a set price in the future, according to Bloomberg.