Kuwaiti European Holding Group now holds a 23.1% share in WH Ireland with its investment.
The announcement today comes after a day of intense media speculation about the deal.
WH Ireland has eight offices across the UK and in the Isle of Man.
Richard Killingbeck, chief executive officer, said: "The board and I are very pleased to welcome our new shareholder in WH Ireland. KEH Group has an exciting plan for growth within its existing financial services companies in the Gulf states and the UK.
“WH Ireland expects to be able to help support this growth from both of its divisions and to benefit from the financial resources within KEH Group to develop and accelerate growth plans at the company."
In a statement, WH Ireland said: “The board welcomes the new shareholder, Kuwaiti European Holding Group and is looking forward to working with KEH Group in order to accelerate the growth opportunities across the company.”
The firm’s roots go back to the founding members of the Manchester Stock Exchange where William Henry Ireland began operating his stockbroking business from the commercial offices in Cross Street.
In the 1980s the company took over J Stephens & Co, a local Manchester broker, before floating on AIM in 2000.
The firm’s head office is in London, with regional offices and an international office in the Isle of Man.