The Virginia state attorney general’s office yesterday said it is looking into a whistleblower lawsuit that accuses Bank of New York Mellon of overcharging the state’s pension funds by using “false exchange rates.”

The lawsuit, which seeks damages of more than $150 million, is the latest in a series of probes where states are accusing custodian banks State Street Corp. and Bank of New York Mellon Corp. of overcharging public pension funds on foreign exchange transactions.

On Thursday, Florida Attorney General Pamela Jo Bondi filed a notice stating that the state would take over a whistleblower suit against Bank of New York. California is also seeking to recover $200 million from State Street for “illegal overcharges” and “fraud” against two of the state’s largest pension funds, CalPERS and CalSTRS.

Both Bank of New York Mellon and State Street said in statements that they are defending themselves against the charges in the suits.

Custodian banks like State Street and Bank of New York typically handle foreign currency transactions on international investments that are held by these large pension funds. Foreign exchange trading has been a big source of revenue and profits at these banks.

Yesterday, the Virginia attorney general’s office said it intervened in the lawsuit filed against Bank of New York under the Virginia Fraud Against Taxpayers Act.

The Virginia attorney general’s office said it appears the bank would charge the most expensive price during the day rather than the actual rate, and then keep the difference.

In trading yesterday, Bank of New York shares closed at $31, while State Street’s stock was off 17 cents to $46.37.