This study empirically examines the relationship between changes in Exchange-Traded Fund (ETF) ownership and corporate decisions to issue Seasoned Equity Offerings (SEOs), utilizing data from the South Korean market between 2016 and 2024. Prior research suggests that rising ETF ownership may amplify stock price volatility through non-fundamental demand shocks and alter corporate information environments. The empirical results of this study demonstrate that increases in ETF ownership are significantly and positively associated with the likelihood of future SEOs. This positive association is especially pronounced among small-cap firms, high-volatility firms, and firms listed on KOSDAQ, suggesting that the link between ETF ownership and SEOs is stronger in settings where information asymmetry is greater. By documenting the connection between changes in ETF ownership and corporate financing strategies, this study contributes to a deeper understanding of how the proliferation and growth of ETFs in financial markets influence corporate financing decisions.