The British are coming! The British are coming! The March 7 announcement that British defense firm BAE Systems would pay $4 billion for Pentagon contractor United Defense Industries tells us two things. First, if there was any question after the invasion of Iraq, there should be no longer: the U.S. and Britain are in this together. The two combined companies will be the sixth-largest supplier to the Pentagon. Second, the acquisition highlights what many growth investors like about mid-tier companies: they are juicy takeover targets. On the day BAE’s offer valued UDI at $75 a share, UDI’s stock closed at $73.35, 25.9 percent above its previous close.

Speaking of Britain and acquisitions, advertising behemoth WPP Group led the list of TR 100 gainers in the five weeks ending March 11, climbing 17.8 percent. The company has made a habit of eating competitors whole (Grey Global, Young and Rubicam), and investors bid the stock up in the wake of strong year-end results. These WPP folks must know what they’re doing. Or do they? Long-suffering Sony shareholders also enjoyed a boost during the month, as a shaking up of the venerable company – most clearly evidenced by the elevation in March of gaijin Howard Stringer to CEO – continued. A month before, Sony had made another big decision. It dumped WPP subsidiary Y&R from a $100 million account.