Ohio and Pennsylvania have joined a group of states that reached a $9.345 million agreement with five investment companies accused of overcharging customers for small investments.

The companies involved — Edward Jones, LPL Financial, RBC, Stifel, and TD Ameritrade — were investigated because regulators thought their fees were unfair. Over five years, the companies collected about $19 million from processing 1.12 million small stock trades across the country.

In Ohio alone, at least 40,000 investors have lost nearly $600,000 because of these fees, and the Division of Securities thinks that number will go up.

Laws prohibit investment companies from charging unreasonable commissions. Federal regulations suggest that a commission of 5% or less of the investment amount is usually fair. However, many of the fees charged by these companies were higher than 5% of the money people invested.

The agreement was announced by the North American Securities Administrators Association. The investigation was led by regulators from several states, including Alabama, Iowa, Massachusetts, Missouri, Montana, Texas, and Washington.

As part of the settlement, the investment companies have agreed to pay back the affected customers, plus 6% interest starting from the date they made the transaction. They will also pay fines totaling up to $9.345 million to the states involved and cover the costs of the investigation. On top of that, each company must put new rules in place to help prevent them from charging too much in the future.