FOS data for the last six months of last year showed there were 816 new complaints involving financial advisers between July and December 2017, compared to 966 for the first six months of the year.
Of the new complaints for the second half of the year, 34% were upheld, also down on the previous statistics, with 43% upheld in the first six months of 2017.
Sesame received 88 complaints taking the top spot, followed by St James's Place Wealth Management on 58.
The only other financial advice businesses included in the list was Openwork, which received 61 complaints, and Hargreaves Lansdown, which received 50.
The figures only cover financial businesses where the ombudsman received at least 30 new cases and resolved at least 30 cases in the six-month period from 1 July to 31 December last year.
Complaints against all four featured firms also fell over the period.
Bank of Scotland had the highest number of new complaints of all financial services firms in the last six months of 2017, with 20,386, with the majority relating to PPI.
HSBC, Barclays and Lloyds Bank were also in the top five, along with Financial Insurance Company Limited, the holding company for Axa, which had 16,613 complaints about PPI.
Barclays Bank received the most complaints about investments (337)
Prudential had the most complaints about life, pensions and decumulation (236).