Toronto, August 1, 2018 – Onex Corporation (“Onex”) (TSX: ONEX) today announced it has
completed an investment in PowerSchool Group LLC (“PowerSchool”), the leading education
technology platform for K-12 schools. Vista Equity Partners is an equal equity partner with
Onex. Onex’ investment was made by Onex Partners IV, its $5.7 billion fund.

About Onex
Onex is one of the oldest and most successful private equity firms. Through its Onex Partners
and ONCAP private equity funds, Onex acquires and builds high-quality businesses in
partnership with talented management teams. At Onex Credit, Onex manages and invests in
leveraged loans, collateralized loan obligations and other credit securities. Onex has more than
$32 billion of assets under management, including $6.7 billion of Onex proprietary capital, in
private equity and credit securities. With offices in Toronto, New York, New Jersey and
London, Onex and the team are collectively the largest investors across Onex’ platforms.
Onex’ businesses have assets of $49 billion, generate annual revenues of $31 billion and employ
approximately 207,000 people worldwide. Onex shares trade on the Toronto Stock Exchange
under the stock symbol ONEX. For more information on Onex, visit its website at
www.onex.com. Onex’ security filings can also be accessed at www.sedar.com.

This news release may contain forward-looking statements that are based on management’s
current expectations and are subject to known and unknown uncertainties and risks, which could
cause actual results to differ materially from those contemplated or implied by such
forward-looking statements. Onex is under no obligation to update any forward-looking
statements contained herein should material facts change due to new information, future events
or otherwise.

For further information:
Emilie Blouin
Director, Investor Relations
Tel: 416.362.7711