WorldCom former accounting executive Buford Yates has pleaded guilty to securities fraud and conspiracy and will cooperate with the Feds in obtaining the dirt on his bosses in a massive accounting fraud, the Associated Press reports.

"WorldCom officials have said roughly $7 billion was misreported, and reports have pinned the final figure as high as $9 billion," the wire service says.

Yates is said to have handled the major dirty work involved in concealing $3.8 billion in company expenses on orders from former CFO Scott Sullivan. Yates is the second WorldCon exec to plead guilty, following former comptroller David Myers. His former boss, Sullivan, has also been charged with securities fraud but has not yet pleaded.

Fellow employees Betty Vinson and Troy Normand, both accused of doing crucial legworkwork for Sullivan and Myers, are expected to cop pleas in the near future, which ought to ratchet up the pressure on Sullivan to plead and give up the Grand Prize, former CEO Bernard Ebbers, who has protested his innocence continually since the scandal broke. ®