Standard Life's Stakeholder with-profits pension plans were hit by market volatility and lost 1.2% during the first half of the year.
The funds, which do not have investment guarantees, dropped 1.2% over the six months to the end of June (on an estimated gross return basis).
They have the highest equity weighting of Standard Life's with-profits plans at 57.9% at the end of June. The remainder of the funds was in fixed interest and other assets but not property.
Market volatility hit the plans in 2010 after a stronger period in 2009, when they rose just over 19%.
All of Standard Life's other with-profits plans increased in value over the first half of 2010, although with-profits bonds only rose 1.8%. They had an asset split of 43.8% in equities, 39.7% in fixed interest and other assets and 16.5% in property. The highest return over the period was 6% for unitised with-profits life and pension funds.
Standard Life said despite the market volatility, all annual bonus rates on its with-profits plans had been maintained.
Final bonus amounts vary according to the plan and its payment history. They are currently being paid on many unitised with-profits plans but MVRs apply to others.
The average MVR on with-profits bonds is 6.4% but there are currently no MVRs on plans taken out between August 2001 and December 2005, or after October 2008.
Two global vehicles
'Further plug advice gap'
Must appoint separate CEOs and boards
Advisers do come out well
Will report to Mark Till