Oct 7 (Reuters) – Mortgage software provider Optimal Blue and nearly 30 major lenders including Rocket Mortgage, CrossCountry Mortgage and United Wholesale Mortgage have been accused in a federal lawsuit of conspiring to inflate residential mortgage fees for millions of U.S. homebuyers.

The proposed class action, opens new tab was filed on Monday in Nashville, Tennessee, by homeowners in Tennessee, Minnesota, Delaware and Rhode Island who claim the lenders used Optimal Blue’s pricing software to share non-public data on interest rates and fees, allowing them to coordinate pricing in violation of federal antitrust law.