Companies with a proactive communications strategy will be better placed to minimise possible member distress over defined contribution asset falls, Fidelity says.
The provider said many of the nation's 5.3 million DC members will face a "nasty shock" when their 2008 annual statement is sent out.
However, it said companies that employ an effective communication strategy are more likely to have an engaged and motivated membership.
Fidelity said long-term analysis of UK stock market returns shows that every "lost decade" of negative annual returns - on a rolling basis there have been 17 since 1899 - markets bounce back with a decade of strong average annual total returns.
The average annual fall in a "lost decade" is 3% but the decade immediately afterwards sees returns of almost 11% a year, for 10 years.
Fidelity International head of UK DC Julian Webb said member communication will play a vital role as statements are distributed.
He said: "The UK stock market had its second worst year ever in 2008 and, with most DC investments exposed to it in some way, I would expect most statements to show a reduced projected pension value.
"Companies need to work with their advisers to set these falls in the context of the long life of a pension - they need to head off hasty decision making and demonstrate how time can help a pension recover from market falls."
He added:" Member communication is a vital component of DC pensions. It helps people see the benefits of joining a company scheme and it nudges them towards more informed decision making."IFAonline
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