The stock market collapse one week ago was driven by worldwide medical fears – over which interest rates and government spending have little influence.  

The market plunge was a gut punch for investors everywhere, including Iowa, where prices for the state’s 17 largest publicly traded companies fell by as much as 22% and as little as 4%. 

The major market indexes – the Dow, S&P 500 and Nasdaq – all posted losses of 10% to 12% for the week of Feb. 24-28.

Five Iowa companies did better than the indexes, three matched the 10-12% decline, and nine posted losses of more than 13%.  

Iowa’s best performer was one of the state’s smallest publicly traded companies. Ames National Corp. is a bank holding company with a market value of less than $250 million where fewer than 10,000 shares change hands on most days. Ames National shares lost 4% during the final week of February.  

By contrast, Principal Financial Group, Iowa’s largest publicly traded company, was one of the state’s biggest share-price losers. The Des Moines-based insurance conglomerate has a market value of more than $12 billion and a normal trading volume of more than 1 million shares a day. Its shares lost 18% of their value during the week. 

Only one Iowa company, West Des Moines-based American Equity Investment Life Holding Co., had a larger share-price loss, 22%. American Equity specializes in insurance annuities and is the state’s second-largest publicly traded insurer, after Principal.

Iowa’s two other publicly traded insurers also had a bad week. Shares of FBL Financial Group, a life insurer based in West Des Moines, lost 16%, while United Fire Group, a property-casualty insurer in Cedar Rapids, lost 15%. 

By comparison, losses among seven of the nation’s largest publicly traded insurers ranged from 11% to 19%. 

Iowa’s banks did better than its insurers, led by Ames National. 

Shares of West Des Moines-based West Bancorporation were down 9%, while Iowa City-based Midwest One Financial lost 10% of its value. Both did markedly better than Wells Fargo and U.S. Bank, which lost 14% each.

Heartland Financial, a Dubuque-based bank holding company, was not as fortunate. It lost 16% of its value during the week.

Two Iowa companies that have been among the state’s best performers in recent years – retailer Casey’s General Stores of Ankeny and financial tech provider Workiva of Ames – each lost 9% during the week, about average for their industries.

What wasn’t average was that both Casey’s and Workiva ended the brutal week with share prices above their year-end closes. Casey’s was up 3% for the year and Workiva was up 2% at a time when half of Iowa’s public companies were down 15-30% for the year. 

Shares of Muscatine-based office furniture maker HNI lost 17% during the week, which compared with losses of 14% each for peers Herman Miller and Steelcase.

Recreational vehicle maker Winnebago Industries in Forest City lost 15% at a time when two of its peers lost 12% and 22%.

Renewable Energy Group, a biodiesel and renewable diesel producer based in Ames, saw its shares lose nearly 13% during the week, placing it at the high end of losses by the major market indexes. Even so, the alternative fuel provider bested two major oil producer/distributors. Shares of Phillips 66 lost 16%, and Marathon Petroleum Corp. lost 20%. 

Finally, Heartland Express, a North Liberty, Iowa, trucking company, saw its shares fall 10% during the week, which was better than three peer carriers, whose shares fell 11%, 13% and 18%.