Understanding how capital gains realizations respond to changes in capital gains tax rates is critical for understanding the potential revenue effects of these changes. A frequently relied on estimate of this responsiveness, or elasticity, comes from Dowd, McClelland, and Muthitacharoen (2015). Using individual-level federal tax return data, they found a short-term (within the current year) tax elasticity of -1.2 and a long-term (beyond the current year) tax elasticity of -0.72. More recently, several studies have found smaller long-term elasticities in absolute value, suggesting less taxpayer responsiveness and a larger potential revenue gain from higher capital gains tax rates. This paper replicates the original Dowd, McClelland, and Muthitacharoen (2015) estimates and investigates their sensitivity to model specification changes including additional lagged tax rates, dropping taxpayers that migrated across states, and limiting the sample to millionaires. We find that introducing additional lags reduces the elasticity to between -0.41 and -0.59, with the most lags producing the largest elasticity. Restricting to taxpayers who don’t move to another state increases the elasticity to -0.65. We are unable to produce precise estimates for our sample of millionaires. Although more research is necessary, this suggests that an elasticity of -0.6 may better capture the effect of tax rates on gains.