Subseries consists of records related to Manson's personal investments, investments made on behalf of others, and trusts managed by Manson. These trusts include the Alexander Malcolm Manson Trust (often abbreviated as AMMT), the Beckwith Trust, the Stella Manson Trust, and the M. M. Trust. The earliest records in this subseries were created while Manson was attending law school and continue until shortly after Manson's death.
Records in this subseries include stock certificates, annual reports, shareholder reports, licenses, leases, land and road surveys, statistics, meeting minutes, statements of return, balance sheets and ledgers, and correspondence with trustors and with companies. Mining companies are particularly well-represented among Manson's records, most notably Germansen Mines Limited. Other investments represented include oil companies and laundries.