Fraser and Gordon Morrison, the two brothers who head the company, will each retain a 27.3 per cent shareholding worth pounds 21m.
The Morrison family bought the company from Charter Consolidated for an undisclosed amount at the peak of the property market in 1989.
The placing and intermediaries offer of shares will raise pounds 18.75m net of money for the company. Morrison's directors are collectively selling pounds 5m of shares.
Group profits have climbed in each of the last two years, hitting a record pounds 7.6m before tax for the 12 months to 31 March. Assuming a notional dividend of 4.26p for the 1994/95 year, the flotation shares yield a gross 4.63 per cent and are on a historic price earnings multiple of 11.25 times earnings.
Morrison attributes its profits growth to its avoidance of the industry's price war.