Since the 1980s, the United States has witnessed increasing wealth concentration in the hands of the ultra-rich. Measured at the state level, the top 10 percent of income earners amassed roughly 43% of total income, and economic growth only enhanced this inequality between the ultrarich and the rest of citizens. This paper examines whether social capital plays a positive role in mitigating income inequality at the state level, with an emphasis on racial diversity and its relation to church attendance. The empirical findings demonstrate that social capital, whether measured by Robert Putnam’s state-level social capital index (SCI), or a new measure that improves SCI’s original measurement, fails to improve income equality. In comparison, racial diversity is found to be a consistent contributor of income inequality. In states with a greater proportion of minority population, the ultra-rich tend to share more wealth and social capital potentially facilitates the ultra-rich to enjoy the benefit of economic growth.