SCOTLAND’s best known business siblings, Sir Brian Souter and Ann Gloag, have ended their joint investment business to follow “their own very different investment strategies”.

The tycoons, who founded Stagecoach in 1980, have divided the assets of their Highland Global Transport investment vehicle between Souter Investments and Gloag Investment Group.

Those assets, as of March 2015, were valued at £613 million.

Accounts for Souter Investments, just filed at Companies House, show the decision to split was made a year ago.

The accounts show this was done “in order to simplify and consolidate the Souter family investment structure”.

Sir Brian could not be reached for comment on the rationale behind the move. Ms Gloag refused to comment on the deal. The siblings continue to have joint property interests, and each have stakes in the luxury interiors business, Clive Christian.

ANALYSIS: Changed priorites ahead for Stagecoach duo

Highland Global Transport (HGT) was formed by Sir Brian and Ms Gloag in 2012, and predominantly held stakes in transport companies, including Stagecoach, Alexander Dennis and the New Zealand-based InMotion group.

Sir Brian was chairman of HGT and owned more than 50 per cent but less than 75 per cent of the shares in the business. Ms Gloag owned more than 25 per cent but less than 50 per cent.

In October 2016, on the same day ownership of the HGT business was transferred, Souter Investments acquired the entire share capital of Highland & Universal Securities (HUS), and Revloch. Both these businesses had been established in 1997 and were owned by various Souter family members and trusts.

Gloag Investment Group was incorporated in February 2016. In one of its first moves, the company embarked on a joint venture to acquire and develop a city centre office block in Edinburgh.

Elsewhere in the Souter Investments accounts, Sir Brian said it had been a “disappointing” year.

The company’s accounts show that net assets fell by £30m to £367m, driven by a 17 per cent reduction in the market value of the group’s stake in Stagecoach, which fell to £182m from £219m.

Stagecoach shares hit a seven-year low when it reported its annual results in June. Profits fell by 80 per cent after troubles on the loss-making Virgin Trains East Coast rail service.

The group has also struggled in the US, where low oil prices are increasing car use.

Writing in the Souter Investments accounts, Sir Brian said: “[The £37m reduction in the value of the holding] obviously had an adverse impact on the group’s performance.”

Souter Investments did however narrow pre-tax losses to £33m, from £84m, helped by a 16.8 per cent uplift in the value of its other investments, to £270m.

“We continue to diversify our portfolio and retain a healthy appetite for unlisted investments,” he said. “While the results for the year were disappointing this masks the significant value that has been added to the portfolio by our employees and managers of our investee companies throughout the course of the year.”