Kingspan founder and chairman Eugene Murtagh has made €44.5m from selling a tranche of his shares in the company.
A stock exchange notification by the Cavan-based specialist building materials business shows Mr Murtagh, earlier this week, sold one million of his shares in the company at a prie of €44.50 each.
Mr Murtagh, who handed over the day-to-day running of the group to his son Gene in 2005, still holds around 181 million shares in the group, representing a near 15% shareholding.
Kingspan shares closed down by over 1.2%, but the stock is up by over 13% over the past 12 months.
Earlier this month, the building insulation group issued a strong first trading update of the year, saying revenues rose 18%, year-on-year, in the first quarter to €1.06bn.
The group said it saw a strong start to trading this year across the US, Canada and Latin America, while its operations in mainland Europe traded "solidly".
Despite Brexit uncertainty, Kingspan said first quarter sales in the UK were "positive", although order intake for its core insulated panels division was "relatively subdued" in the period.
Kingspan, also this month, ruled out resurrecting a €700m bid for the insulation division of Belgian group Recticel. Gene Murtagh told shareholders at Kingspan's recent agm that Recticel refused the bid despite Kingspan twice reaching a provisional agreement to buy.
Analysts are upbeat about Kingspan, with expectations for trading profits to grow by up to 9% this year to over €480m and the group's balance sheet being strong enough to allow for a number of acquisition opportunities to be realised.