Helbert, Wagg developed investment management services from the 1920s. Four investment trusts were established in the interwar years:
- British and German Investment Trust, set up in 1926, renamed the Broadstone Investment Trust in 1937
- Trans-Oceanic Investment Trust, set up in 1928
- Westpool Investment Trust, set up in 1931
- Ashdown Investment Trust, set up in 1937
Records about these trusts include: accounts; information about investments; governance matters; financial and administrative papers.