UPDATE 2-HK's BEA shares soar on suitor talk, but hurdles remain

* BEA shares soar as much as 26 pct over 2 days on M&A talk

* Guoco bid would face anti-trust issues in Malaysia

* Spain's Criteria stake capped at max 20 pct under BEA deal (Recasts with comments from BEA, Guoco)

By Alison Leung and Doug Young

HONG KONG, Nov 12 (Reuters) - A battle for control could be brewing for Hong Kong's No.5 bank, Bank of East Asia (0023.HK), pitting one of the former British colony's oldest families against newer interests from Europe and Southeast Asia.

But any bid could face a number of obstacles, including anti trust laws in one potential suitor's home market, and a previous agreement by the other not to launch a hostile bid for the company.

Rumours that Malaysia-controlled conglomerate Guoco Group (0053.HK) could be interested in BEA -- which saw a run on its deposits just a year ago at the height of the global financial crisis -- have sent the bank's shares up as much as 26 percent in the last two days.

Spain's Criteria CaixaCorp (CRIT.MC), BEA's current largest single stakeholder with 9.04 percent of its shares, could also try to increase its stake in the bank.

But a Guoco purchase of BEA -- which owns 20.5 percent of Malaysia's AFFIN Banking Group -- would violate Malaysia laws prohibiting one group from owning two banks in the country. Guoco's owner, Quek Leng Chan, already owns a Malaysian bank through his Hong Leong group.