The action has been filed in New York by five former employees and one current worker at the investment bank.
According to the claimants, the bank operated with a âboys clubâ mindset and laid off a number of women in favour of retaining less qualified men within the firm.
Five of the claimants were among those made redundant by Citigroup during November 2008 at the height of the global credit crash.
The court documents, which were quoted by the Wall Street Journal, said: âWhile Citigroup has worked so hard to right the ship and repay [Troubled Asset Relief Program] funds borrowed from the federal government, it has failed to address the pervasive discrimination and retaliation that its female employees have been subjected to throughout the course of their employment.â
In the complaint, the claimants also cite the gender make up of its senior leadership committee and executive committee as evidence of the firm's gender bias.
The former, which consists of 44 individuals, features five women while the latter made up of only males.
Citigroup issued a statement refuting the claims saying: âMany of their allegations are either totally inaccurate or selectively incomplete.â
By Jim Ottewill