"We've filed with the intent to provide access to insurance for all Iowans, whether they are farmers, small business owners or other individuals who need coverage".
Medica - which now has 14,000 Iowa members - quickly became the only hope for the majority of Iowan's relying on subsidy-eligible plans through the individual insurance exchange.
During the first week of April, Wellmark Blue Cross & Blue Shield and Aetna announced they were pulling out of the Iowa market after this year.
Medica said its rates in Iowa for 2018 would average 43.5 percent higher than this year.
The increase is because "a number of risks remain with its decision to provide coverage across Iowa". "We will continue to work with federal and state officials to provide the certainty and stability needed for markets to succeed long-term".
It's not clear what effect the filing might have on the Iowa Insurance Commissioner's request that the Trump administration approve a stopgap measure aimed at dealing with what officials called a collapsing individual marketplace.
Iowa Insurance Commissioner Doug Ommen had said last week the plan was the only alternative to an individual marketplace void of choices.
"Rate increases of 43 percent are not sustainable long term", Bartsh said.
"The bottom line is that the individual market still needs reform", he said.
The state's stopgap plan would allow companies to sell a single, standardized insurance plan, restructure Affordable Care Act subsidies and create a reinsurance pool to help with high-cost patients. It was viewed as an effort to keep Medica in the Iowa market while luring others back.
Medica plans this year cover about 70,000 people in Iowa, Minnesota, North Dakota, Nebraska, Kansas and Wisconsin.