Canonsburg-based simulation software maker Ansys Inc. has struck a deal to buy Ansoft Corp. for approximately $832 million in cash and Ansys common stock.

Executives for the two companies touted the deal as a joining of complementary strengths. Ansoft, headquartered in Station Square, develops software to automate the design of such products as integrated circuits and networking components.

The boards of both companies unanimously approved the transaction, which will create a company with combined revenue of $485 million and 1,700 employees.

The deal is expected to close by June 30.

Ansoft stockholders would receive half of the $832 million being offered in cash; for the other half, each share of Ansoft will be swapped for approximately .43 of a share of Ansys.

In their joint statement, the companies said the deal implied a purchase price of $32.50 per share of Ansoft, a 39 percent premium over Friday's closing stock price of $23.42.

Investors sent decidedly mixed signals on the transaction. Ansys' stock dropped by 9.52 percent, to $34.52 from $37.92, while Ansoft rocketed more than 30 percent to close at $30.52, up from $23.42.

A certain degree of convergence between the prices of an acquiring company and the company being acquired is common after a deal is announced, as investors try to figure out how to price the combined entity.

But yesterday's price action suggested that there was more involved than that typical arbitrage, one analyst said.

"There may be some concern on the part of some analysts or fund managers that the size of the transaction may make it a difficult one to integrate effectively and speedily," said Elliott Schlang, analyst with Soleil Securities' Great Lakes Review, a Cleveland-based boutique research firm.

"But we think Ansys has already earned its stripes" by the speed and efficiency with which it integrated another acquisition two years ago, Mr. Schlang said.

In February 2006, Ansys announced a deal to buy Lebanon, N.H.- based Fluent, a provider of engineering software and services, in a $565 million cash-and-stock transaction that also was "greeted with some skepticism."

"We think this is an exquisite acquisition for Ansys," Mr. Schlang said.