Butane stock levels nearly doubled in October 2009 from their stock levels in the previous year, rising from 1.1 million barrels to 2.1 million barrels. This stock level was also 2% greater than the September 2009 stock level and 39% greater than in May.

While the butane stock level continued to rise in October, which is the most recent data available from the U.S. Energy Information Administration (EIA), it didn’t seem to affect the price as butane prices rose US17¢ at Conway and 7¢ at Mont Belvieu from September 2009 to October 2009. The stock level was the second highest it has been in the month of October over the past 17 years, so this price increase came in spite of normal market dynamics and reflected a greater overall push in NGL prices.

The EIA defines normal butanes as "a normally gaseous straight-chain hydrocarbon. It is a colorless paraffinic gas that boils at a temperature of 31.1º F. It is extracted from natural gas or refinery gas streams." – Frank Nieto