Mercury Interactive

(MERQ)

has agreed to buy privately held

Appilog

for $49 million in cash, the Mountain View, Calif., company said after the close of trading on Wednesday.

Appilog, a 4-year-old software vendor, had "negligible" revenue last year, but the acquisition will not affect the acquiring company's second quarter, said Chris Lochhead, Mercury's chief marketing officer. The acquisition is expected to close in June or July.

Most of Appilog's approximately 40 employees will likely join Mercury, he said.

Mercury's products are used by large businesses to monitor and improve the performance of applications running on data networks. Appilog's technology will enhance the diagnostic capabilities of Mercury software.

Mercury will report its June quarter results the week of July 19th.

On Wednesday, shares of Mercury gained 8 cents, or less than 1%, to close at $44.76.