US companies will need to inject more than $100bn into their pension funds to cover market losses, putting them in a cash squeeze at a time when it is difficult to raise money.

The cash payment, estimated by several pension industry executives, would be spread over this financial year and next year.

Companies’ pension fund losses – running at an estimated 20 per cent in the year to date – also are expected to alter earnings this year, partly because of accounting changes.

The 700 largest corporate plans were more than 100 per cent funded at the end of last year, but as of last week that had fallen to about 83 per cent, according to estimates by Mercer, a pension consultant.

John Erhardt, a principal at Milliman, a consulting firm, said: “To bring company funds back to 100 per cent funding, companies would need to put in about $50bn this year and that again next year, for the top 100 funds. You could add another 30 per cent to 40 per cent to that for the rest of the funds.”

“Earnings will be impacted significantly. The 2008 year-end balance sheet will reflect that.”

Mr Erhardt said there were about $300bn in fund losses to the end of this month.

After the introduction of the Pension Protection Act this year, that would go “straight on to the company balance sheet”.

A report by Credit Suisse estimated that at the end of September there were 136 companies that would need to lift contributions to their pension plans by half or more.

It said 76 companies had seen a drop in funded levels for their schemes that was greater than 5 per cent of their corporate book value.

These included seven companies where the drop was more than 25 per cent of book value: Unisys, Qwest, Embarq, Ford, Western Union, Dean Foods and Pactiv Corp.

David Zion, who wrote the report, estimated that apart from the cash payout, there were 65 companies whose earnings could be cut by 10 per cent because of an increase in pension costs.

The change to earnings is separate from the cash infusion necessary to shore up the funds.

The American Benefits Council, which represents corporate pension plans, is lobbying for the federal government to suspend some of the PPA rules, which require mandatory contributions if funds fall below a certain level.