The French company GDF Suez has bought the 30 per cent of IP it does not already own, in a move that will boost the company's profile on the global economic stage.
GDF Suez bought the British-owned firm for £6.8 bn at 418p per share. IP owns 45 power stations, six of which are in the UK.
GDF chairman and chief executive Gerard Mestrallet said that the takeover would allow his firm to "fully capture growth in fast-growing markets."
A spokesperson for GDF said:
"The offer enables GDF Suez to take full control of a unique platform for development in fast growing countries, where the group intends to significantly increase its investments in the future."
Analysts have said that the move is a strategic one for GDF given IP's strong growth prospects. IP shares were up 3.3 per cent at 417.3 pence in London, while GDF was up about 1 per cent in Paris to 18.15 euros.
IP shareholders will receive a dividend of 6.6 euro cents.