January RBOB prices opened sharply lower Tuesday evening but remained trapped inside of yesterday's wide-ranged advance overnight. Some traders pointed to private industry data that revealed an enormous build in US gasoline supplies as being behind the overnight weakness. Expectations for this morning's EIA report are for a build in US gasoline supplies in the range of 750,000 to 1.0 million barrels. While it is possible that the gasoline market has rallied off of a number of refinery problems that have reduced short term supplies, demand remains soft and running around 5.0% below year-ago levels.