By Anna Louie Sussman NEW YORK, Jan 14 – JPMorgan Chase & Co slightly raised its commodity trading risk for the first time since last spring in the fourth quarter, even as it exits the physical commodities trading business, its quarterly results showed on Tuesday. Value-at-Risk (VaR) in commodities at JPMorgan, the largest U.S. bank, rose to $15 million in the fourth quarter, from $13 million, unchanged during the previous two quarters, and up $1 million from the fourth quarter of 2012. JPMorgan, typical of Wall Street banks, groups its commodities revenue under the fixed income category and does not break out the sector, often leaving VaR as one of its key risk-reward indicators that can measure commodities exposure. For the fourth quarter, fixed income revenue was $3.2 billion, down from $3.4 billion in the third quarter and in line with the fourth quarter of 2012.