Standard Life said the launch of pensions auto-enrolment helped it add another 195,000 workplace policyholders in the first nine months of the year as take-up of the scheme remains strong.
The Edinburgh-based firm said auto-enrolment contributed to a 53% increase in the value of new corporate pension premiums, with more than 100 schemes set up so far this year.
The programme was launched by the Government a year ago to automatically place up to 10 million people in company pensions.
Standard Life said early progress remains "encouraging", with less than 10% of employees opting out.
Standard Life posted a 20% hike in new business sales to £17.3 billion in the first nine months after sales rose 18% in the third quarter, while assets under management rose 9% to a record £237.6 billion since the start of the year.
But the new business figures were slightly lower than expected, sending shares in the group down 4%.
Worldwide net inflows of long-term savings business - up 11% at £2.8 billion - also missed analyst forecasts.
Experts said Standard Life was partly suffering from a drop in new business into its previously popular investment product, the Standard Life Global Absolute Return Strategies fund, which has been hit by the departures of top fund managers and recent poor performance.
Barrie Cornes, analyst at Panmure Gordon, said despite coming in below City expectations, Standard Life had reported a "solid set of life and pension new business figures".
He added the group was starting to benefit from auto-enrolment and this year's Retail Distribution Review (RDR) overhaul that banned commission payments to financial advisers.
Standard Life said it had a strong pipeline of corporate pensions, with further benefits expected from auto-enrolment throughout 2014.
The group also increased funds under management for its DIY pension product - self-invested personal pension (SIPP) - by 14% to £21.4 billion in the first nine months of the year.