Data from the FCA shows complaints related to investment advice totalled over 17,000 in the second half of 2016.
The number of complaints against personal investment firms, which include advisers, rose nearly 10,000 from 23,300 to 33,200.
Complaints regarding advising, selling and arranging of investments totalled just over 17,000, while decumulation and pensions complaints stood at 5,400.
Complaints against investment managers also increased nearly 10,000, hitting 51,600.
Year-on-year comparisons are not available as following new FCA rules, more complaints were reported in the second half of 2016 as previously complaints closed within one business day were not included in the data.
The proportion of personal investment complaints upheld held steady at around 39 per cent. Nearly half of complaints against investment managers were upheld.
Nearly 9,000 complaints were received about non-workplace personal pensions, including Sipps. Structured products and investment trusts each had fewer than 100 complaints.