More than a decade since its introduction, the polymeric excipient Soluplus continues to receive considerable attention for its application in the development of amorphous solid dispersions (ASDs) and its utility as a solubilizer for drugs exhibiting solubility limited absorption. While it is well-recognized that Soluplus forms micelles, the impact of its lower critical solution temperature of approximately 40 °C remains an underexplored aspect. This study investigated the phase behavior of Soluplus in fasted-state simulated intestinal fluid (FaSSIF-V1). It was demonstrated that Soluplus forms a dispersed polymer-rich coacervate phase, which coexists with Soluplus micelles at 37 °C. This behavior was confirmed by cloud point measurements, visually discernible phases after centrifugation, as well as multi-angle dynamic light scattering (MADLS) measurements, and quantitative