New Mountain Capital, a New York-based investment firm, to invest in Ontario Systems, a provider of enterprise software. Financial terms were not disclosed. With its purchase of a majority share in Ontario Systems, New Mountain Capital will replace Arlington Capital Partners as the Company’s largest investor. “The New Mountain team’s expertise in growing software businesses will be invaluable as we look to deepen our revenue cycle management offerings and continue providing our customers market-leading solutions they have come to trust. Building on the momentum of this transaction, I look forward to working closely with New Mountain to unlock unique growth opportunities,” Jason Harrington, Ontario Systems President.