A bid to move a huge billion dollar US industrial conglomerate's headquarters to Bermuda could be in jeopardy after a takeover bid was launched on Wednesday.

Industrial giant Danaher Corp. Wednesday made an unsolicited bid to acquire Cooper Industries Inc. for up to $5.5 billion.

Cooper's, which has a broad line of electrical products, tools and hardware, wanted to move its global headquarters from Huston to Bermuda, and shareholders were due to vote on the issue in several weeks time.

The offer pushed Cooper shares up $10.99, or almost 26.5 percent, to $52.50 in morning trading on the New York Stock Exchange.

If Cooper's shareholders moved to Bermuda, analysts told Reuters that a hostile takeover bid would become substantially more complicated and expensive.

"This is a compelling transaction for both companies from both an industrial and financial perspective," said Danaher President and Chief Executive H. Lawrence Culp Jr. "We believe Cooper shareholders will find our proposal preferable to Cooper's proposed reincorporation in Bermuda, especially given Danaher's long history of superior performance relative to both market indices and Cooper's shares."

Danaher said its cash-and-stock offer is worth between $54 and $58 per share, a premium of 30 percent to 40 percent over the company's $41.51 closing price on the New York Stock Exchange on Tuesday.

Including the assumption of debt, the deal would be worth between $6.5 billion and $7 billion.