(Corrects figure in headline)
* Sells 4.94 percent stake at 3 percent discount
* Books 266 million euro capital gain
* Iberdrola shares down 3 percent
MADRID, April 10 Spain's biggest state-owned lender Bankia booked a 266 million euro ($368 million) gain from the sale of its 4.94 percent stake in Spanish utility Iberdrola, the latest in a series of asset disposals to bolster capital.
Spain's bailed-out banks like Bankia have been selling corporate holdings to comply with the terms of a 2012 European rescue and to address new regulatory demands.
Bankia sold its Iberdrola stake to institutional investors for 1.53 billion euros at a price of 4.85 euros per share, representing a 3 percent discount to Iberdrola's closing price on Wednesday, the bank said on Thursday.
UBS and Citigroup had acted as joint book runners on the sale through an accelerated book build.
Iberdrola's shares, which were suspended from trading before the announcement, resumed 3.14 percent lower at 4.845 euros, underperforming an 0.25 percent fall on Spain's blue-chip index .
Bankia has already sold stakes worth more than 2.4 billion euros in groups such as airline holding IAG, insurer Mapfre, IT company Indra and hotelier NH Hoteles.
"For Bankia, this is an important step forward in the divestment of its industrial portfolio, as this (Iberdrola) was the bank's largest asset in this portfolio," Banco Espirito Santo said in a note to clients.
Bankia still owns 24.95 percent of property firm Realia , 2.99 percent of Mapfre, 19.1 percent of unlisted property firm Metrovacesa and 16.5 percent of olive oil firm Deoleo, which is currently the target of a bid by CVC Capital Partners..
Its shares were up 0.61 percent at 1.49 euros by 0836 GMT.
($1 = 0.7234 Euros) ($1 = 0.7234 Euros) (Reporting by Tracy Rucinski; Editing by Erica Billingham)