Takeovers show economy is nearly back to normal

Wall Street's mergers and acquisitions machine is recovering from its recession doldrums, raising the old question of whether the takeovers investment banks foster do anything more than make companies bigger and harder to manage.

Schlumberger Ltd this week said it would buy oil-field services rival Smith International Inc for about $11 billion and, according to Bloomberg News, Thermo Fisher Scientific Inc is offering about $6 billion for Millipore Corp, adding biotechnology customers to its market for laboratory equipment.

There already have been some eye-popping deals. Exxon Mobil Corp, the biggest US oil company, in December offered about $31 billion for XTO Energy Inc, to add the target company's huge reserves of natural gas.