Pension deficits causing concern in West Country
Bristol-based Imperial Tobacco has the biggest pension deficit in the West.
The figure of £842m has been worked out by taking the total amount needed to pay pensioners in the future minus the investments held by the pension fund.
Michael Harvey, from BBS Actuaries, said the deficits represented a real problem to businesses.
Swindon-based Nationwide had a deficit of £287m. In Somerset Clarks shoes has a deficit of £142m, and Westland Helicopters £115m.
Mr Harvey added: "If companies are spending all their money protecting the pension scheme, they'll have less money to invest in the business.
"That potentially means less job security, and potentially less future jobs."
The research by Bristol-based BBS Actuaries examined company accounts of the 100 biggest companies in the West.
This revealed a combined deficit of £2.6bn.
BBC West business correspondent Dave Harvey said the list reads like a Who's Who of businesses in the region.
"Imperial Tobacco, Westlands, Wincanton, they're all there.
"Companies that used to employ thousands of people, many of whom are now retired and drawing the pension they were promised.
"But now there are many fewer staff paying in to the schemes, and the pension fund hasn't done as well on the stock market as they'd hoped," he added.
It is believed the deficits have arisen because people are living longer after retirement and the financial crisis has reduced the value of pension fund investments.