By Faith Hung

TAIPEI (Reuters) - Taiwan financial conglomerate Taishin said it would raise its offer for peer Shin Kong by 25% to about T$222.4 billion ($7 billion), in a deal that would be Taiwan's biggest-ever financial services industry merger.

Taishin and Shin Kong's long-mooted tie-up, announced last month, has had to contend with an unexpected rival bid from CTBC Financial to acquire Shin Kong, though the target says it views Taishin as its preferred bidder.

Taiwan's financial services industry tends to be quite domestically focused, and Taishin and Shin Kong hope that by merging they can expand their footprint and become a more globally competitive firm while building long-term value.

Taishin will offer 0.672 common shares and 0.175 preferred shares per Shin Kong share for a 100% stake in the revised all-share deal, sweetening the pot from the 0.6022 common share swap offered previously, Taishin and Shin Kong said late on Wednesday.