An extensive, on-going investigation into the effectiveness of a micro-emulsion (ME) as a stimulation fluid additive is being conducted. Results from a population of 114 wells and 498 stimulation stages of hydraulic fracture stimulation provide the basis for this report. As part of the basis for the performance analysis, twenty four of the wells are producing from the Lance interval in the northeastern Pinedale Anticline area of the Green River Basin, Wyoming. The remaining 90 wells produce from the northern Denver-Julesburg Basin Codell and Niobrara formations. In both data sets about half of the wells had 1.5 gallons of ME per thousand used throughout the fracture stimulations, but at no other time during in-well operations. The stimulation fluid systems in the remaining wells contained no similar interfacial tension / surfactant system. Based on the performance matched reservoir properties and degree of effective stimulation, these comparisons and other performance metrics were used to assess the potential benefit arising from using ME. The determination of potential benefit was assessed using classical statistical methods to ensure that the interpretation was as unbiased as possible. From that analysis, there is distinct and clear benefit to be gained from using the micro-emulsion to facilitate placing the fracture stimulations, to increase effective fracture length and especially to increase hydrocarbon recovery from the wells in which the micro-emulsion system is used.