We present a model of ESG integration where borrowers can deviate from ESG promises ex-post. Borrowers get lower financial gains from reneging on their ESG claims as their borrowing cost is high. However, competition with non-ESG investors lowers the borrowing rate, deterring ESG integration. Nevertheless, when ESG-friendly investors bid first, they can contribute to ESG integration when borrowers privately know their genuine preferences for ESG. Specifically, there is an equilibrium where ESG-friendly investors take out non-ESG borrowers from the market, so the subsequent investors perceive the holdout borrowers as ESG-friendly and demand a higher borrowing rate, facilitating ESG integration.