The new regulatory regime, Solvency II, could add up to 10% to pension buyout deals, according to PwC.
It said the directive, which harmonises insurers in the EU, would require firms to hold more capital to support buyout business written from January 2016.
PwC advised companies and pension scheme trustees who want to transfer their defined benefit (DB) pension liabilities to insurers to "complete the deals soon or expect to pay up to 10% more from next year".
PwC said the 10% figure was based on an analysis of trends in insurance pricing, but it would depend on the proportion of retired and deferred members in a scheme.
Jerome Melcer, PwC's pensions director and buyout adviser, said: "Insurance companies have to have high reserves for those individuals [deferred members], otherwise the profitability will be affected seriously."
He said the duration of liabilities would affect capital requirements. For example, for younger members, such as those aged 40 or 45, liabilities might extend to another 50 to 60 years, while for those aged 75 or 80, liabilities might be 15 to 20 years.
PwC predicted a surge of activity in the buyout market in the coming weeks, as pension schemes would "rush to complete deals this year before the price hikes".
It said around £13bn worth of DB pension liabilities were passed to insurers in 2014 and a further £5bn to date in 2015, as companies wanted remove these "unpredictable and long-term liabilities" from their balance sheets. Melcer predicted by the end of the year, around £10bn to £13bn worth of buyout deals could be made.
Melcer said: "Any companies considering a pensions buyout in the next few years should buy now or could end up paying later, due to the price hikes Solvency II will bring.
"Companies or trustees looking at the business case for buyout will need early, reliable, price visibility before pressing the button on buyout."