FINRA was investigating how companies marketed ETNs and other complex products, according to recent reports.

Last month, FINRA permanently barred a former Morgan Keegan registered rep for putting some of his clients into leveraged ETFs that were unsuitable. [Broker Barred Over Leveraged ETF Investments]

Leveraged and inverse ETFs are designed for traders hoping to capture short-term market swings.

“But FINRA is concerned that brokers are selling these products to long-term retail investors, despite the dangers with holding on to these products for more than a day,” Reuters reported Wednesday.