Filings for stock market-listed Vertu Motors show that Mr Hydes has increased his stake from 3.3pc to 4.1pc.
The holding is currently valued at about £9m (€10.5m).
Mr Hydes has made the investment in Vertu Motors via an Irish company called Nivag Holdings that is wholly owned by him.
He also controls Joe Duffy Motors via Nivag and shares held directly in his name.
The businessman initially passed a 3pc ownership threshold in Vertu in November last year, when it was reported to the stock exchange that Nivag owned 3.3pc. Investors must notify the stock market when they pass a 3pc ownership level in a listed company.
Since the end of November, shares in Vertu, which are listed on London’s Alternative Investment Market, have declined by about 22pc.
As of yesterday, the company had a market capitalisation of £223m.
Yesterday’s regulatory announcement shows that Nivag raised its stake in Vertu Motors last Friday.
Vertu was formed in 2006 to acquire and consolidate UK motor retail businesses. It now has a chain across the UK of 188 franchised and non-franchised motor dealerships for cars and commercial vehicles.
They operate as Vertu Motors, Bristol Street Motors and Macklin Motors.
In Scotland, it owns the Macklin Motors brand, which deals in marques including Ford, Hyundai, Kia, Mazda, Nissan, Peugeot, Vauxhall and Toyota.
Vertu generated revenue of just over £4bn in the year to the end of February 2023, compared with £3.6bn in the previous financial year.
However, its adjusted profit before tax plunged by 50pc to £39.3m.
The company said last month that used-vehicle values in the UK have stabilised at a lower level following a downturn in recent months. It also said new vehicle sales in the UK had declined year-on-year, with manufacturers discounting prices and enhancing offers in an effort to boost sales.
“Despite the impact of the complex market dynamics on the short-term performance of the business, the current market presents opportunities for Vertu with our strong balance sheet providing financial flexibility,” said chief executive Robert Forrester at the time.
Joe Duffy Motors bills itself as Ireland’s largest car dealership network.
It represents 17 brands and has more than 20 locations across the country.
The firm made a profit after tax of €18.7m in 2022, up from €15.2m in 2021, the most recently publicly available accounts for the business show. Its revenue increased to €545m from €457.3m.
