Mark Leonard worked in venture capital before he founded Constellation Software in 1995. His idea was to buy small vertical market software companies, hold them permanently and put the cash into the next purchase.
The company went public on the TSX in 2006. In 2013 it bought Total Specific Solutions for $360 million. Operating groups kept running their own businesses while capital allocation stayed in one place.
In 2018 the company stopped holding quarterly earnings calls, and in 2021 it spun off Topicus.com. Leonard stopped taking a salary in 2016.
In September 2025 he stepped down as president and Mark Miller took over. Revenue had reached $10.07 billion in 2024, with net income of $767 million.