Thirty percent of eligible General Motors retirees accepted a lump sum payment in lieu of ongoing pension benefits, according to the company's most recent 8-K filing with the U.S. Securities and Exchange Commission.

It also announced that it expects to close in early November a transaction through which The Prudential Insurance Company of America will assume responsibility for pension obligations covering GM's remaining eligible U.S. salaried retirees.

Through annuitizations and lump sum payments, GM will have eliminated $29 billion in U.S. salaried pension liability, which was much higher than the initial $26 billion estimate. As part of these transactions, the auto maker will contribute $2.6 billion to its pension plan and will record an estimated $2.9 billion pre-tax charge in the fourth quarter as a special item.