Six companies are missing from last year’s list. Three of them are gone after being acquired.

Three others are gone for a variety of reasons from a headquarters move, to the expiration of a trust and a stricter change in the list methodology.

Life Time Fitness ranked 27th on last year’s list. The company, while still headquartered in Chanhassen, went private in March 2015 in a deal valued at $4 billion.

Ridley Inc. barely made its debut at No. 44 on the 2015 list. The company was registered in Canada but had its roots and executive headquarters in Mankato, so it fit the criteria and we included the company for the first time last year.

However, the animal nutrition company has since been acquired by Kentucky-based Alltech Inc. for $428 million. At the time of the deal the companies said employement and management in Mankato wouldn’t change.

Eagan-based Norcraft Holdings, a manufacturer of kitchen and bathroom cabinetry,ranked 49th last year was acquired by Fortune Brands Home & Security in a deal valued at $528 million. Fortune Brands is headquartered in Deerfield, Ill.

Golden Entertainment, ranked 69th last year, is no longer on the list after moving the company headquarters to Las Vegas.

The move makes sense. Formerly known as Lakes Entertainment, the company changed its name and address in 2015 after acquiring Golden Gaming Inc., which runs slot machines in Nevada and operates four casinos. The approximately $55 million deal closed in August.

Great Northern Iron Ore Properties, ranked 86th last year, deregistered in April 2015 after the trust expired. The trust managed the mineral and nonmineral rights on the Mesabi Iron Range in northeastern Minnesota.

The iron ore interests were originally acquired by Louis Hill, son of railroad pioneer James J. Hill. By design, the trust agreement was set to expire 20 years after the death of the last survivor of 18 persons named in the trust agreement.

WSI Industries, a contract manufacturer based in Monticello, ranked 73rd a year ago and would be 69th this year on 2015 revenue of $42.6 million, but we removed local over the counter stocks from the list this year.