* Proceeds mostly to refinance group's debt
* Offering size may be increased to 1 billion euros
* Shares fall 8.5 percent
(Adds shares, detail, comment)
By Dominique Vidalon and Leila Abboud
PARIS, Sept 2 (Reuters) - Telecoms equipment supplier Alcatel-Lucent said it plans to raise up to 1 billion euros ($1.4 billion) by issuing convertible bonds to help it refinance its debt, pushing its shares lower on Wednesday.
The company initially said it would launch a 750 million euro bond, but raised the amount to 870 million shortly before 1000 GMT following better-than-expected demand.
The joint lead managers and bookrunners have an additional option to increase the bond issue to 1 billion euros by Sept. 8, Alcatel-Lucent added in a statement.
Shares in the company were 8.5 percent lower at 2.334 euros by 1016 GMT, the worst performers on a 0.8 percent weaker French benchmark CAC 40 index. The volume on Alcatel shares represented 190 percent of the stock's 90-day daily average.
Traders attributed the drop to some investors selling the shares to acquire the bond.
The bond issue had been expected by some analysts, while Alcatel-Lucent executives had floated the idea earlier in the year. It is seen by some as a positive move for Alcatel-Lucent because it puts the group on a sounder financial footing.
"This will alleviate investor worries about the balance sheet," said one London-based analyst.
Alcatel-Lucent carries about 4 billion euros in long-term debt. It also has large pension obligations from the former Lucent, which it funds in accordance with U.S. pension laws.
The new bonds will bear interest at a rate of between 5.00 percent and 5.50 percent per year payable semi-annually in arrears on Jan. 1 and July 1 of each year, starting Jan. 1, 2010, the company said.
"The principal purpose of the offering is to contribute to the refinancing of the group's debt and the extension of its maturity, and, secondarily, to further enhance the group's financial position," Alcatel-Lucent said in a statement.
Separately, South Korean media reported Alcatel-Lucent was among candidates shortlisted to buy Nortel Networks Corp's stake in LG-Nortel.
An Alcatel-Lucent spokesman declined to comment on the report.
Canada-based Nortel is selling assets after filing for bankruptcy earlier this year and has already auctioned off its lucrative CDMA wireless business. (Editing by James Regan and David Holmes) ($1=.7023 Euro)