Pilot Flying J's corporate offices are pictured in this file photo.

• 1. Pilot Flying J, Knoxville truck stop chain, $29.2 billion in revenues with 25,000 employees

• 2. HT Hackney, food distributor in Knoxville, $3.8 billion in revenues with 3,499 employees

• 3. ServiceMaster, a Memphis-bsed business service and supplies company with revenues of $3.2 billion and 21,000 employees

• 4. Life Care Centers of America, nursing home and senior center chain based in Cleveland, Tenn., $2.75 billion in revenues with 38,000 employees

• 5. Iasis Healthcare, hospital chain based in Franklin, Tenn., with revenues of $2.26 billion with 14,285 employees

Source: Forbes, 2012