Forrest Media, which will be folded into Ocean Scotland, has sites in Edinburgh and the centre of Glasgow as well as inventory in Manchester and Newcastle.
The deal further builds on Ocean’s strategy to create a larger out-of-home media company through consolidation and follows Ocelot Partners’ £200m acquisition of the company in March.
Ocean Outdoor’s portfolio had already included sites in Manchester, Edinburgh and Glasgow alongside well-known London venues such as the Piccadilly Lights, the BFI Imax in Waterloo and Westfield’s Holland Park Roundabout.
Ocelot’s move for Ocean signalled a catalyst for further M&A activity in a sector with several OOH businesses that are owned by private equity and with consolidation thought to be overdue.
Tim Bleakley, chief executive of Ocean, said: "Forrest are the champions of OOH in Scotland and it’s a business we have long admired."
The Forrest Media management team will continue under the day-to-day leadership of managing director Marc Keenan.
Chris Trainer, the founder of Forrest Group, becomes chairman of Ocean Scotland. He is the third biggest shareholder in Scottish football champions Celtic and is launching a nine-story hotel in the Clydeside area of Glasgow, The Herald reported in April.
Trainer added: "Ocean are a fantastic market leading business and the combination today with Forrest Media now delivers a truly national ‘footprint’, which we believe will have very significant benefits in our industry, with great opportunities for the whole team."
Ocean has also entered into new long-term lease agreements with other Forrest Group entities for sites that it owns.