Historically, September has been the poorest performing month of the year for stocks, and this year was no different. Most major indexes registered a decline on the month. Market uncertainty still looms due to several factors such as lofty stock valuations, increasing COVID-19 case numbers, the replacement of Supreme Court Justice Ruth Bader Ginsburg and heated U.S. election campaigns.

Fifteen of the 18 Iowa-based companies on the Business Record's Iowa Index posted stock price losses for the month. Five companies posted double-digit percentage losses. Only three Iowa-based stocks posted gains, all double-digit gains. 

Renewable Energy Group Inc. had the largest gain of the month with a 59.80% increase. Flexsteel Industries Inc. had the second-biggest gain at 44.75%. FBL Financial Group had the third-biggest with a 30.09% increase.

United Fire Group Inc. posted the biggest percentage loss at 19.30%. Ames National Corp. had the second-biggest loss with a 15.34% decrease. Heartland Financial USA Inc. was third with a 12.87% decrease.

The Iowa Index, an unweighted average price of 18 Iowa-based public companies, increased 1.63% in September, compared with a 5.16% decrease in the Nasdaq stock index and a 2.28% decrease in the Dow Jones industrial average. 

The Iowa-based companies that make up the Iowa Index are in bold in this list of companies with sizable operations in the state.

See the full Iowa Index