By REPORTER ASSOCIATES Sara Hammes and Tricia Welsh

(FORTUNE Magazine) – The companies below belong to an exclusive club. Its ranks are fixed by the Department of Defense, which every fiscal year draws up a list of the contracts it has awarded and who received them. In 1989, the latest year available, these amounted to $129 billion. The DOD excludes contracts by which other U.S. government agencies, such as NASA or the Department of Energy, spend its money. The Pentagon 25 consistently account for 50% of the total and rarely boast new members. McDonnell Douglas and General Dynamics have been in the top three for nine years running. A few that collect the odd big-ticket contract, such as GTE -- No. 38 in 1988 and No. 11 in 1989 -- drop in and out. Similarly, Tenneco steams into the top ten whenever the Navy orders up a nuclear aircraft carrier.