Currency investors risk leaving money on the table if they don't submit claims on a $2.1 billion pot of settlement money paid by banks accused of rigging foreign-exchange rates.

That's the message from Battea FX Group, which is competing in the business of advising clients on how to get their share of the payouts. Its seven former FX traders and executives are helping firms recover funds from class actions claiming that some of the world's biggest banks conspired to manipulate the $5.1 trillion-a-day currency market. Fourteen banks have settled, including Bank of America Corp., Barclays, Citigroup Inc., HSBC Holdings and Royal Bank of Scotland Group.

Here's how it works: Companies that traded currencies with the dealers from 2003 to 2015, including hedge funds, asset managers, pension funds, corporations and even other banks, hire Battea or one of its competitors. The advisory firm crunches data from deals in spot, forwards, options, swaps and futures markets, seeking to recover as much money as possible via a court-appointed claims administrator, and it gets a contingency fee based on the amount awarded.