It is two steps forward and two steps back for Minnesota entries on the annual Fortune 500 list.

The deal announced Thursday for Eden Prairie-based Supervalu Inc. to be purchased by Providence R.I.-based United Natural Foods Inc. is likely to mean that Minnesota will lose another company on the list.

A spokeswoman for United Natural Foods said Friday that no decision has been made on where the combined company will have its headquarters.

But if it goes to Rhode Island, that would be Minnesota's second loss on Fortune's list of the biggest corporate headquarters this year, bringing the state's total to 17.

The magazine's latest rankings, published this spring, showed Minnesota was home to 19 of the nation's 500 largest companies by revenue. Since then, Plymouth-based Mosaic Co., ranked No. 382 on the list, has announced plans to move its headquarters to Florida, where it has major phosphate production.

Last year, the magazine listed 18 Fortune 500 firms in the state. With this year's update, St. Jude Medical, which was acquired by Chicago-based Abbott Laboratories, disappeared. Meanwhile, the state received two additions as strong revenue growth lifted St. Paul-based financial services firm Securian Financial Group up to No. 462 and Medina-based Polaris Industries Inc. to No. 496.

The next Minnesota-based company that may join the Fortune 500 is Winona-based Fastenal Co., which climbed to No. 566 from No. 591.

The Fortune 500 list ranks U.S. companies by total revenue and includes companies that are required to make regular financial filings with a government agency. That's why the magazine's list includes two Minnesota cooperatives, Land O'Lakes and CHS Inc.; a mutual company, Securian Financial; and nonprofit fraternal benefit organization, Thrivent.

The Fortune 500 doesn't include private companies or companies whose headquarters are registered overseas. That leaves out Minnetonka-based agriculture giant Cargill Inc. and Medtronic PLC, which is legally based in Ireland but the company's executive headquarters is in Fridley.

At about $14 billion in annual revenue, Supervalu was ranked No. 180 on the latest Fortune 500, but it has been slipping in recent years as it sold off some of its retail chains. Last year, it was ranked No. 158 and five years ago it was ranked No. 94.

United Natural Foods, with about $9 billion in annual revenue, was ranked No. 319 on the latest Fortune 500 list.

Fortune also ranks companies, where applicable, by market capitalization as of March 29. Supervalu's market cap was about $585 million at that time, putting it at No. 913 on Fortune's overall list of big companies. After Thursday's announcement, Supervalu's share price jumped, lifting its market value to $1.24 billion.

Staff writer Kristen Leigh Painter contributed to this report.