Private master's comprehensive institutions (PMCIs) in the United States navigate pressures to expand college access and equity while striving for prestige in the academic hierarchy. To strive for prestige entails competing for world-class status of greater selectivity, research intensity and resources, but such a pathway to excellence may, because of market-competition, deepen institutional and student stratification in the sector. In this study, we examine how organisational characteristics associated with striving influence low-income student enrolment at PMCIs over time. Our panel analysis revealed selected factors constraining the enrolment of low-income students at the average PMCI. But the magnitude of these statistical relationships was rather modest and did not suggest dramatically worsening institutional and student inequality in the sector. These findings support a flexible theory of organisational fields, illuminating more equity-centred behaviours at the typical PMCI than what prior literature indicates. We discuss implications for research and policy emphasising equity's connection to institutional excellence.