Acquisitions and relocations resulted in the usual departures from our list. And UnitedHealth Group's supercharged growth combined with those departures widened the gap between No. 1-ranked UnitedHealth -- now with more than $100 billion in revenue -- and this year's No. 100, Wireless Ronin Technologies with $9.3 million in sales.

GONE

•Lawson Software (No. 35 last year) was acquired for about $2 billion by Infor and Golden Gate Capital on July 16, 2011.

•Health products giant Baxter completed the acquisition of Synovis Life Technologies (No. 72 last year) in February for approximately $325 million.

•Endo Pharmaceutical acquired American Medical Systems (No. 44 last year) in June for $2.9 billion in cash.

•Vital Images Inc. (No. 75 last year) became part of Toshiba Medical Systems Corp. in a $273 million deal.

CHANGE OF ADDRESS

•Alliant Techsystems moved its top management to Arlington, Va., to be closer to its largest customers -- such as the Defense Department -- and the nation's capital. The company moved just a few dozen people, and most of the Minnesota operations remain in the state, so we've elected to keep it in the list for at least one more year.

•MoneyGram International moved its headquarters to Dallas in 2010. MoneyGram has big operations in Texas, but it helped that CEO Pamela Patsley had a home there.

•Minnesota has benefited from this arrangement before. OneBeacon is a Bermuda-domiciled specialty insurance holding company, with management headquarters in Minnetonka. It has made the list several years now and approximately 50 of OneBeacon's 1,200 employees are based in Minnetonka.

NEW BLOOD

•Proto Labs Inc. joins the list this year at No. 68. The quick-turn maker of custom parts launched a successful initial public offering in February, pricing at $16 a share. The shares have traded as high as $39.08 but closed Friday at $30.32. The company provided year-end 2011 financials, so we welcomed them aboard.

•HEI Inc. (No. 82) and Broadview Institute Inc. (No. 94), are both going concerns with compelling stories -- even if their shares are thinly traded. HEI makes ultraminiature microelectronic devices and had revenue in 2011 of $37.4 million. Woodbury-based Broadview Institute, which operates Broadview University and Broadview Entertainment Arts University, provides online education. The company has $18.3 million in revenue and campuses in Utah and Idaho.

•Digital Angel Corp. dropped from No. 84 to 103rd. During 2010 and 2011 Digital Angel sold several businesses, including its Destron Fearing business, so its annual sales fell.

•Two small publicly held medical firms that specialize in the urology field ranked at the bottom of our list last year. For the second year in a row, Urologix Inc. ranked No. 99 while Uroplasty Inc. jumped seven spots to No. 93.

PATRICK KENNEDY