* Chile"s peso the sole Latam gainer * Mexico seeks natural gas supply guarantee after Texas export ban * Brazil"s real dips on full day of trading after long weekend (Adds details, updates prices) By Susan Mathew and Ambar Warrick Feb 18 (Reuters) - Mexico"s peso led losses across Latin American currencies on Thursday as a prolonged energy freeze in the U.S. state of Texas disrupted activity across the border, while higher U.S. yields pressured risk-driven assets. The peso lost 0.8% as the shutdowns in the United State"s largest energy producing state due to poor weather affected power generation in Mexico. The Mexican government pressed for natural gas supplies after Texas implemented a ban on exports. "In addition to concerns about an unusually strong winter in some parts of the country and its effect on the economic recovery process, the debate about as to whether and if so to what extent monetary policy will be eased further will be affecting the (Mexican) peso most," said Elisabeth Andreae, FX analyst at Commerzbank. "Following the appointment of a new board member the uncertainty about this matter is particularly high, as it is unclear to what extent Banxico will deviate from its current course." A rise in U.S. treasury yields drove flows out of risk-driven assets, as more investors bet on increased fiscal spending and debt issuance to fish the economy out of a pandemic-induced slump. The U.S. Labor Department"s report showed initial claims for state unemployment benefits rose over the prior week, denting hopes of a steady economic recovery and furthering the case for more stimulus. Brazil"s real fell on its first day of full trading after an extended weekend, extending losses after a slide on Wednesday when it traded for half a day. Chile"s peso rose slightly to a more-than six-week peak, taking some support from copper prices hitting a nine-year high. Chile is the world"s top producer of the red metal. As has been the case since the pandemic began about a year ago, losses in Latam assets were much larger than their broader emerging market peers, as investors perceived the region"s economies as much more fragile. Latam stocks tumbled, with the MSCI"s index of equities set for its worst day in three weeks. Brazilian stocks shed 1.3% as broad-based losses offset gains in commodity stocks. Shares in Carrefour Brasil rose 1% after it said it is "optimistic" about margins and as its French parent posted solid full-year results and announced further cost cutting and cash flow targets. Key Latin American stock indexes and currencies: Latest Daily % change MSCI Emerging Markets 1425.17 -1.37 MSCI LatAm 2386.05 -1.24 Brazil Bovespa 118763.31 -1.32 Mexico IPC 44714.76 -0.77 Chile IPSA 4523.43 -0.78 Argentina MerVal 51838.34 -1.047 Colombia COLCAP 1361.02 -0.39 Currencies Latest Daily % change Brazil real 5.4369 -0.41 Mexico peso 20.3625 -0.76 Chile peso 711.7 0.21 Colombia peso 3545.5 -0.56 Peru sol 3.6507 0.00 Argentina peso 89.0500 -0.11 (interbank) (Reporting by Susan Mathew in Bengaluru; Editing by Andrea Ricci and Alistair Bell)