NEW YORK (Real Money) -- One of the core themes at the start of the year for those forecasting 3.5% or better GDP growth for the U.S. economy in 2015, including the International Monetary Fund, was that the huge drop in gasoline prices would act as a substantial "tax cut," boosting consumer spending and the economy.

So far, those forecasters have been wrong in that assumption.

Editor's Note: This article was originally published at 8:30 a.m. EDT on Real Money Pro on May 14, 2015.

This article is commentary by an independent contributor. At the time of publication, the author was long in General Motors and Sequential Brands Group.