Mimecast Ltd. /zigman2/quotes/202578603/composite MIME +0.54% announced Tuesday an agreement to be acquired by private equity firm Permira in a deal that values the email-security software company at about $5.8 billion. Mimecast's stock is currently halted for news until 7:30 a.m. Eastern. Under terms of the deal, Permira will pay $80.00 for each Mimecast share outstanding, which is 6.7% above Monday's closing price of $75.00. The deal, which is expected to close in the first half of 2022, comes more than a month after The Wall Street Journal reported that Mimecast was exploring a possible sale. Since then through Monday, Mimecast's stock had rallied 8.8%. Mimecast's deal with Permira includes a "go-shop" period that expires on Jan. 6, 2022. The stock has run up 32.0% year to date, while the ETFMG Prime Cyber Security ETF /zigman2/quotes/207892345/composite HACK -1.99% has gained 2.5% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -1.89% has advanced 22.3%.