UPDATE 2-Spain's CAM says could make another placement

* CAM board agreed to issue more certificates * Board to limit portion of its "available surplus"

(Adds placement cap)

MADRID, Oct 23 (Reuters) - Spain's Caja de Ahorros del Mediterraneo (CAM) (CAHM.MC) said on Thursday it could list more participation certificates -- which are like non-voting shares -- on the stock exchange.

In a statement, the savings bank said its board had agreed to issue more certificates without setting a date for a placement, but had sought authorisation to do so within three years.

The bank added that the board would limit the portion of its "available surplus" to be placed at 17.5 percent.

CAM went public on July 23, the only Spanish savings bank to have done so, when it placed 292 million euros of certificates.

Savings banks in Spain's Mediterranean region lent heavily to real estate and construction companies which now account for over 25 percent of all defaults as house sales and prices fall. (Reporting by Clara Vilar; Writing by Martin Roberts; Editing by Quentin Bryar and Sharon Lindores)