One of the smallest banks in Texas is challenging the world’s largest credit union, claiming in a proposed class action lawsuit that the $180 billion Navy Federal Credit Union has lax Know Your Customer procedures that allegedly facilitate business check fraud.

The lawsuit, filed by the $122 million Buckholts State Bank (BSB) last week in U.S. District Court in Austin, Texas, alleged the Vienna, Va.-based Navy Federal Credit Union has allegedly acknowledged the average single check fraud transaction amount is $10,000 and that approximately 19,200 fraudulent checks (worth an estimated $192 million) are transacted annually, affecting over 100 downstream banks. Navy Federal, which has managed to limit its own losses to about 1% of the total fraudulent accounts exposure, allegedly stated during a deposition that it was not “shocked by that number,” according to the lawsuit.