It is buying the group from LDC, the private equity arm of Lloyds Banking Group.
Paul Thandi, chief executive of the NEC Group, said: “Blackstone get what makes us stand out and they’re fully behind what we want to achieve.
“We look forward to continuing our journey with all our valued clients and we’re committed to constantly improving our offer.
“The sale won’t create any immediate change and our management team will continue in their current roles following completion of the sale.”
LDC originally backed a management buyout of the group in January 2015. Since then, it has supported a four-year programme to enhance sites, facilities and customer experience and broaden the range of events across the group’s portfolio with ‘significant capital investment’.
“Blackstone’s track record in scaling companies, sector knowledge and unrivalled real estate capabilities, make them the ideal new partner for NEC Group to realise the next phase of our ambitious growth strategy,” said Thandi.
“All of our teams and partners look forward to working closely with the world class team as we embark on becoming the definitive name in events and exhibitions, while continuing to focus on innovations and new customer experience offerings for all our customer groups.”
Lionel Assant, Blackstone’s European head of private equity, added: “The NEC has transformed its main site into a leading leisure, entertainment and business destination, which continues to benefit from a diverse customer base.
“We have tremendous respect for what has been achieved; NEC Group is iconic and we are excited about our new partnership as we look to leverage our firm’s capabilities in support of the team.”
Founded in 1976, the NEC has grown into one of the leading UK live events businesses, playing host to over 7m guests and 750 events every year.
The NEC boasts Birmingham's National Exhibition Centre, the International Convention Centre, the Genting Arena and Arena Birmingham among its assets as well as caterer Amadeus and national ticketing agency The Ticket Factory.
* In June The Irish News reported that Amadeus had 'lost' a £16m contract to provide catering at the Belfast Waterfront and Ulster Hall following a performance review. It was two years into a five-year deal