UPDATE 1-Alcoa's Belda to retire as chairman next year

* Chairman Alain Belda to retire as executive officer

* Belda to remain chairman until April 2010

* CEO Klaus Kleinfeld expected to succeed Belda

NEW YORK, May 29 (Reuters) - Alcoa Inc (AA.N) said on Wednesday that Chairman Alain Belda will retire as an executive officer of the aluminum company effective Aug 1 and will likely be replaced by President and Chief Executive Officer Klaus Kleinfeld next year.

The company said in a filing with the Securities and Exchange Commission (SEC) that Belda was expected to continue to serve as chairman until his term as a director expires at the annual shareholders meeting next April 23.

"It is anticipated that Klaus Kleinfeld...will succeed Mr Belda as chairman," the filing said.

German-born Kleinfeld, who joined Alcoa from the global electronics and industrial conglomerate, Siemens AG (SIEGn.DE), in August 2007, succeeded Belda as CEO in May 2008. Belda, a Brazilian, was CEO from 2001 and has had a 40-year career at Alcoa.