In its latest financial report filed on Companies House last week, Innovision declared profit before tax of £143,645 compared with £718,102 in 2015.
Operating profit, which calculates how much the company made from business operations, also fell by 80% from £716,669 to £145,405.
Turnover, however, rose by 27% from £15.7m in 2015 to £19.9m for the year ended 31 December 2016.
The financial report noted that Innovision paid out almost an extra £1m in "administrative expenses". In 2016 the agency paid out £5.6m, compared with £4.7m in 2015.
The agency is run by husband and wife team Andrew and Claudia Douglass, and celebrated its 20th anniversary last year.
Innovision did not respond to Campaign's requests for comment.