The century-old biennial show, will formally become part of the Emap Construct division on 7 July but the hand-over began at this year's event, held at the NEC from 25-29 April.
Montgomery first entered what proved to be a somewhat strained joint venture with Emap in 1998 when it sold 50% of Interbuild, which it wholly owned, to the publishing giant. The Midlands event has since been organised under an Emap Montgomery banner.
Emap Construct managing director Graham Harman said it was always Emap's intention to buy the remaining shares from Montgomery. "When the original joint venture was set up there was always a possibility for us to acquire Montgomery's share after the 2006 show, so we've just brought it forward," he said.
Montgomery managing director Christopher Newton dismissed speculation that the sale of the show would hurt the company. "We're launching shows and developing business fast. It's fair to say we might be looking more at developing markets and there has been a change of focus."
The Interbuild branded subsidiary events belonging to Montgomery in Africa and India will stay under the Interbuild banner. Emap will retain the NEC show's sales and marketing staff, while the organiser staff will remain with Montgomery.
Newton added: "We felt the show was better off in the hands of one organiser. We may get involved in other construction events in England on top of our show in Scotland. We also own construction events in Poland, Ireland and Russia."