TOKYO (Reuters) - Japan's Panasonic Corp said it would launch a tender offer for shares in Sanyo Electric Co on Thursday, moving closer to becoming a powerhouse in hybrid car batteries and other green-energy businesses through the bid worth at least 402.3 billion yen ($4.5 billion).

Panasonic said it would offer 131 yen per Sanyo share and aim for a majority stake in the world's largest rechargeable battery maker, reiterating its announcements late last year when the company first made public its intention of taking over Sanyo.

The offer price is down sharply from Sanyo's closing price on Wednesday of 216 yen.

But all three of Sanyo's top shareholders -- Goldman Sachs, Daiwa Securities SMBC and Sumitomo Mitsui Banking Corp, which bought Sanyo shares at a lower price -- have agreed to sell part of their stake into the tender, ensuring that Panasonic will acquire more than half of Sanyo.

Sanyo in 2006 issued 300 billion yen in preferred shares, each of which can be exchanged for 10 common shares, to the three financial institutions at 700 yen a share to help it restructure after a sharp downturn in earnings.

The planned takeover would make Panasonic, which was sitting on cash and cash equivalent of 1.46 trillion yen as of Sept. 30, a dominant player in the fast-growing market for hybrid car batteries.

Customers for Sanyo's hybrid car batteries include Honda Motor Co Ltd, Ford Motor Co and PSA Peugeot Citroen, while Panasonic runs a joint venture with Toyota Motor Corp to develop and make hybrid and electric car batteries.

Sanyo is also a major manufacturer of solar cells and Panasonic offers fuel cells, enabling the new Panasonic group to offer a wide range of environmentally friendly energy-producing and energy-storage products.

Daiwa Securities SMBC is a joint venture between Daiwa Securities Group Inc and Sumitomo Mitsui Financial Group (SMFG), while Sumitomo Mitsui Banking is Sanyo's main bank and part of SMFG.

Prior to the announcement, shares of Sanyo closed down 5.3 percent at 216 yen. Panasonic lost 0.6 percent to 1,254 yen, which was in line with the Tokyo stock market's electrical machinery index .

(Reporting by Kiyoshi Takenaka; Editing by Chris Gallagher)

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