(Bloomberg) -- VMware Inc., the biggest maker of software that lets computers run different operating systems, agreed to buy AirWatch for as much as $1.54 billion to add enterprise mobile management and security services.

Closely held AirWatch, based in Atlanta, has more than 10,000 customers globally and 1,600 employees in nine offices around the world. VMware will pay $1.175 billion in cash and $365 million in installment payments and assumed unvested equity, according to a statement today.

For VMware, majority-owned by EMC Corp., AirWatch will be the second acquisition of more than $1 billion in 18 months, after the 2012 purchase of Nicira, a maker of technology that helps networks work more efficiently.

Preliminary fourth-quarter revenue rose 15 percent to $1.48 billion, Palo Alto, California-based VMware also said today. That’s the high-end of the company’s forecast range and surpasses the $1.47 billion average of estimates compiled by Bloomberg.

VMware’s shares dropped 1.9 percent to $95.50 at 8:23 a.m. in New York, before the markets opened. The stock fell 4.7 percent last year, when the Russell 1000 Index gained 30 percent.

The acquisition will be funded through a combination of balance sheet cash and proceeds from about $1 billion of additional debt to be provided by EMC, the world’s largest maker of storage computers. VMware also said it will also continue with its share buyback program.

The AirWatch transaction is expected to be completed late in the first quarter, according to the statement. Insight Venture Partners invested $200 million in AirWatch in February 2013, according to data compiled by Bloomberg. Accel Partners invested $25 million in May of last year, the data show.