J2 Global has acquired Philadelphia cloud email security provider Excel Micro Inc. – the company’s fourth acquisition in as many months.

Terms of the deal were not disclosed. J2 Global said the acquisition would expand its North American email security customer base, reseller channels and channel expertise.

“This acquisition reflects our ongoing efforts to expand and grow our email security business on a global basis, both organically and through acquisitions,” said Chief Executive Hemi Zucker in a statement.

Those efforts include a buying spree for the Hollywood cloud service provider. J2 Global in late July purchased North Carolina email marketing company Contactology. MXSweep, an email security and encryption service firm in Ireland, was picked up in August. And an Australian domain and web hosting company Web24 Group was bought last month.

Shares of j2 Global were up 9 cents, or two-tenths of a percent, to $49.45 a share midday Wednesday on the Nasdaq stock market.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.