The state attorney general's office is suing Barclays.
The office announced the securities fraud lawsuit on Wednesday, accusing the firm of false statements.
The suit alleges the banking and financial services group of not being up front about its private stock trading platform and its electronic trading division.
It also accuses Barclays of catering to high-frequency traders while claiming they set up safeguards against them.
Barclays has not commented on the accusations.