RSM Tenon has listed on the main market of the London Stock Exchange at an initial value of £139m ($202m).
Upon admission on 27 May, the company’s share price rose 1.5p to 43.25p.
RSM Tenon forecasts it will be eligible for inclusion in the FTSE indices at the September 2010 review.
RSM Tenon announced in early May that it intended to switch from the Alternative Investment Market to the main London Stock Exchange in an effort to reach out to a broader group of investors and grow more rapidly.