Welplan has become the latest occupational defined contribution master trust to obtain independent assurance.
The Pensions Regulator has also added it to its list of master trust pension schemes, which have all been independently reviewed to help to demonstrate a high standard of administration.
Regulator executive director Andrew Warwick-Thompson said: "Master trust assurance provides employers with the confidence to choose [one] that is being operated to a high standard and that can evidence the presence of the quality features we expect to see in a well-run scheme.
"It also acts as a check against providers operating in this marketplace that do not have the necessary resources or competence."
The master trust voluntary assurance framework was developed by the Institute of Chartered Accountants of England and Wales in association with The Pensions Regulator to support auditors to provide independent assurance reports for the trustees of master trusts.