Mexico's stock market sank on Monday and the peso slid after leftist presidential candidate Andres Manuel Lopez Obrador handily won election while his allies picked up a significant number of congressional seats. Mexico's benchmark stock index shed more than 2 percent, its steepest one-day drop in nearly five months, after Lopez Obrador on Sunday won with the widest margin in a presidential election since the 1980s. The 64-year-old former Mexico City mayor's victory was widely priced in by markets, but an apparent better-than-expected showing in congressional races for his leftist party has put investors on edge. Mexico's peso weakened slightly, but its losses were less than other emerging market currencies as the dollar broadly gained with a safe-haven bid amid mounting global trade tensions and political developments in Europe. Sergio Luna, an economist at Citigroup unit Banamex, noted it was surprising there was not more selling with such a big political shift. But he noted that investors would be wary to see how Lopez Obrador's economic policy plans develop. "He has the benefit of the doubt for now, but the market will need to see more granularity on his proposals," Luna said. "There is still an element of suspicion and he needs to address that." Carlos Urzua, Lopez Obrador's pick to be his finance minister when he takes office on Dec. 1, has moved to mollify investor concerns, holding a conference call on Monday. Urzua told Reuters in an interview that Lopez Obrador supports ideas such as creating a fiscal committee for prudent economic management, reform of pensions and cost-cutting at state-owned oil firm Pemex. In his victory speeches, Lopez Obrador said he would respect central bank independence and talks on the North American Free Trade Agreement, among other things. "The conciliatory tone of Andres Manuel Lopez Obrador after his convincing victory in the presidential elections has been relatively well received by the markets," said Capital Economics in a report. "But it's worth warning that we still have little clarity about his economic policies." Latin American stock indexes and currencies at 2055 GMT: Stock indexes daily % YTD % change change Latest MSCI Emerging Markets 1059.32 -0.95 -8.56 MSCI LatAm 2421.24 -2.25 -14.39 Brazil Bovespa 72839.74 0.11 -4.66 Mexico IPC 46653.52 -2.12 -5.47 Chile IPSA 5301.25 0.83 -4.73 Chile IGPA 26843.21 0.73 -4.07 Argentina MerVal 25404.65 -2.43 -15.50 Colombia IGBC 12499.63 1.49 9.93 Venezuela IBC 0.00 0 -100.0 0 Currencies daily % YTD % change change Latest Brazil real 3.9103 -0.88 -15.27 Mexico peso 19.9635 -0.24 -1.63 Chile peso 653.05 -0.61 -5.88 Colombia peso 2929.25 0.00 1.80 Peru sol 3.287 -0.33 -1.52 Argentina peso (interbank) 28.2000 2.66 -34.04 Argentina peso (parallel) 28.9 0.17 -33.46 (Reporting by Gram Slattery, Noé Torres, Sheky Espejo Editing by Grant McCool and Chris Reese)