Most Asian stock markets retreated Monday as worries about Citigroup Inc. weighed on financial shares, but pared some losses after the US government unveiled a plan to rescue the troubled banking giant. Investors largely shrugged off Friday's rally on Wall Street, where major benchmarks surged more than 6 percent as US President-elect Barack Obama appeared ready to tap the New York Federal Reserve chief Timothy Geithner as the next treasury secretary. Overshadowing the news were concerns about the fate of New York-based Citigroup, whose shares plunged last week. Under the plan unveiled late Sunday in the US, Washington would take a $20 billion stake in the bank and guarantee hundreds of billions of dollars in risky assets - moves aimed at shoring up a huge financial institution whose collapse would destabilize further the global financial system and US economy. Citigroup failing "is the last thing investors want to see," said Alex Tang, head of research at Core Pacific-Yamaichi. "That would have a major impact on not only the US market, but on the global market."