Evolution

The pending Delta-Northwest Airlines merger, announced last week after months of rumors, has captured lots of attention, but for now Northwest remains on our list. But if regulators approve the deal, this could be the Red Tail's last appearance on the Star Tribune 100.

Meanwhile, other members of the ST100 were more quietly acquired in 2007. Among them:

Ceridian Corp. (ranked No. 31 last year) came under attack from activist investors for much of 2006 and 2007. It was finally taken private by a consortium including Thomas H. Lee Partners in November. Ceridian, a payroll services and information-management firm, was a spinoff of mainframe computer maker Control Data Corp. in 1992.

Rural Cellular (No. 50 last year) was acquired in July by a consortium led by Verizon for $2.5 billion. Rural was one of many recent deals in the cell phone industry that were about expanding network coverage and reducing network roaming charges. The deal for Rural will close in June.

The telecom consolidation also claimed Eschelon Telecom (No. 63 last year), which was acquired by Integra Telecom for $659 million in September.

MGI Pharma (No. 59) was acquired by Eisai Corp. of Japan in December for $3.6 billion. MGI is a biopharmaceutical company focused on oncology and acute-care products. Its most promising drug is Aloxi, an anti-nausea drug for chemotherapy patients. In 2006, MGI had 540 employees and $343 million in revenue but it attracted a higher price -- $3.6 billion -- than Delta is likely to pay for Northwest.

Perhaps no sector has grown as fast this decade as the ethanol industry. Fueled by a desire for a homegrown energy source and state mandates for the use of ethanol-blended gas, the industry has experienced a rapid buildup and is already consolidating. US BioEnergy went public on Dec. 14, 2006, and a little less than a year later, VeraSun Energy announced its acquisition of US BioEnergy. The $745 million deal closed on April 1. US BioEnergy made its debut on last year's ST100 at No. 77, moved to No. 50 this year, and will be gone from next year's list.

ASV Inc. in Grand Rapids (No. 65 last year) developed an innovative skid steer loader built on tracks instead of wheels. The tracks better distribute the weight and don't tear up the landscape as much as wheeled loaders. Terex Corp. of Connecticut bought ASV on March 4, 2008, for approximately two times annual sales, or $488 million. ASV's Posi-Track loaders will fit in nicely in Terex's product line and ASV will get access to Terex's global sales network.

KMG America Corp. (No. 69 last year) was acquired by health care giant Humana Inc. in September. KMG had headquarters here but most of its business was done by its subsidiary, Kanawha Insurance Co., which sells mostly in the South and East.

Digital Angel (No. 93 last year), which makes implantable identification devices for pets and livestock, was acquired by Applied Digital Solutions on Dec. 31 for $33.6 million

Four companies grew onto this year's list. More accurately, the revenue floor to make the list fell enough to capture them.

Last year the 100th-ranked company had revenue of $43.3 million. This year electronic controls maker Winland Electronics (No. 102 last year) is the 100th-ranked company with revenue of $34.7 million.

Security fence maker Zareba Systems (No. 98 this year) and medical equipment maker Angeion Corp. (No. 97) both make this year's list because the revenue floor is lower.

Revenue at ATS Medical (No. 95), which jumped 22.6 percent to $49.6 million, would have been enough sales to make last year's list.

The other way to join the Star Tribune 100 is through an initial public offering, and three companies made their ST100 debuts after successful IPOs in 2007.

Dolan Media debuts the highest at No. 70. The publisher of legal and real estate publications and provider of foreclosure processing services went public in August. Priced at $14.50 per share, it raised $163 million and was the biggest Minnesota-based IPO of the year.

Virtual Radiologic Inc. (No. 79) of Hopkins completed its IPO on Nov. 14, raising $68 million. The company employs radiologists across the country who interpret and analyze imaging data from CT scans, MRIs and ultrasounds 24 hours a day using encrypted broadband networks.

Compellent Technologies Inc. (No. 94), Eden Prairie, a provider of network storage solutions for business customers, completed its public offering on Oct. 9, raising $81 million.

A fourth Minnesota-based start-up, Enteromedics, a development-stage medical device company that designs devices for obesity-management treatments, went public but does not have enough revenue to make our list.

Prospects for next year's crop of IPOs are slim. Only two Minnesota-based companies have registered for an initial public offering so far this year and neither has completed its offering. Nationally more companies have withdrawn their registrations than have completed IPOs during this year of volatile trading on major stock markets.

PATRICK KENNEDY