An Argon ST shareholder filed a class-action lawsuit July 2 in U.S. District Court in Alexandria, Va., to block the sale of the defense electronics firm to Boeing Defense, Space & Security.

Boeing announced June 30 that it had agreed to buy Fairfax, Va.-based Argon ST for $34.50 a share, or roughly $775 million.

Deidre N. Sullivan, an Argon ST shareholder who lives in Connecticut, accuses Argon ST Chief Executive Officer Terry Collins and 10 directors of breaching their fiduciary responsibilities by agreeing to acquisition terms designed to benefit top executives and certain board members holding large, illiquid blocks of company stock.

The complaint, filed by Washington law firm O’Donoghue & O’Donoghue, alleges that Argon ST directors did not search for competing offers before agreeing to sell the company to Boeing in an all-cash transaction expected to net Collins, Argon ST’s largest shareholder, some $93.7 million.

“Collins will be able to cash out the rest of illiquid equity holdings in the Company and he, along with the rest of Argon’s conflicted management team, are being given jobs with the Company post-merger,” the complaint states. “In fact, Boeing has promised Collins that it will continue to operate Argon as a standalone subsidiary within Boeing, a division of Boeing Network & Space Systems, with Collins’ entire management team intact. Essentially, Boeing has promised Collins that he can have his cake and eat it too — the same position with his Company intact and without the hassles of remaining obedient to public company shareholders in fulfilling reporting requirements.”

Boeing said in announcing the deal it expected the transaction to close by the end of the third quarter of 2010, assuming shareholder approval and the outcome of U.S. regulatory review.

Boeing spokesman David Sidman declined July 8 to comment on the lawsuit.