This paper estimates the impacts of expanding access to consumer credit at a 200% annual percentage rate (APR) using a field experiment in South Africa. The study randomly assigned marginal loans to applicants, and followed up with household surveys and administrative data to measure borrower outcomes. The results show that expanding access to credit significantly improved borrower outcomes across a wide range of economic and subjective well-being indicators. Treated applicants had higher employment and income, better food consumption, and higher levels of subjective well-being compared to controls. However, there was also evidence of a negative effect on another measure of subjective well-being. The average treatment effect across all outcomes was significant and positive. The study also found that the marginal loans were profitable for the lender, although less so than inframarginal loans. The results suggest that welfare-improving interventions in consumer credit markets can be effective, but with important caveats. The study highlights the importance of randomized controlled trials in identifying the severity of liquidity constraints and evaluating efforts to expand credit access. The findings challenge the common presumption that expanded access to expensive credit does more harm than good, and suggest that such interventions can be beneficial in certain contexts. The study also has implications for the methodology of accumulating additional evidence needed to optimize policy and practice. The results are important for policymakers and microfinance practitioners who operate under the strong presumption that expanded access to expensive credit does consumers more harm than good. The study provides evidence to the contrary in a setting where the likelihood of "productive" lending seemed slim ex ante. The findings suggest that randomized experimentation can be used to evaluate the impacts of credit expansion on borrower and lender outcomes. The study also highlights the importance of considering the long-term impacts of credit access, and the potential for debt traps or other delayed realizations of borrowing costs. The study also notes that the external validity of the treatment effects to markets with different competitive structures or consumers with different characteristics is uncertain. The study concludes that the findings are important for both policy and practice, and that the results suggest a role for welfare-improving interventions in consumer credit markets. The study also highlights the importance of considering the heterogeneity of treatment effects across different borrower characteristics. The study also notes that the results may not apply to all markets, and that the external validity of the findings is uncertain. The study also highlights the importance of measuring the long-term impacts of credit access, and the potential for debt traps or other delayed realizations of borrowing costs. The study also notes that the results may not apply to all markets, and that the external validity of the findings is uncertain. The study concludes that the findings are important for both policy and practice, and that the results suggest a role for welfare-improving interventions in consumer credit markets.This paper estimates the impacts of expanding access to consumer credit at a 200% annual percentage rate (APR) using a field experiment in South Africa. The study randomly assigned marginal loans to applicants, and followed up with household surveys and administrative data to measure borrower outcomes. The results show that expanding access to credit significantly improved borrower outcomes across a wide range of economic and subjective well-being indicators. Treated applicants had higher employment and income, better food consumption, and higher levels of subjective well-being compared to controls. However, there was also evidence of a negative effect on another measure of subjective well-being. The average treatment effect across all outcomes was significant and positive. The study also found that the marginal loans were profitable for the lender, although less so than inframarginal loans. The results suggest that welfare-improving interventions in consumer credit markets can be effective, but with important caveats. The study highlights the importance of randomized controlled trials in identifying the severity of liquidity constraints and evaluating efforts to expand credit access. The findings challenge the common presumption that expanded access to expensive credit does more harm than good, and suggest that such interventions can be beneficial in certain contexts. The study also has implications for the methodology of accumulating additional evidence needed to optimize policy and practice. The results are important for policymakers and microfinance practitioners who operate under the strong presumption that expanded access to expensive credit does consumers more harm than good. The study provides evidence to the contrary in a setting where the likelihood of "productive" lending seemed slim ex ante. The findings suggest that randomized experimentation can be used to evaluate the impacts of credit expansion on borrower and lender outcomes. The study also highlights the importance of considering the long-term impacts of credit access, and the potential for debt traps or other delayed realizations of borrowing costs. The study also notes that the external validity of the treatment effects to markets with different competitive structures or consumers with different characteristics is uncertain. The study concludes that the findings are important for both policy and practice, and that the results suggest a role for welfare-improving interventions in consumer credit markets. The study also highlights the importance of considering the heterogeneity of treatment effects across different borrower characteristics. The study also notes that the results may not apply to all markets, and that the external validity of the findings is uncertain. The study also highlights the importance of measuring the long-term impacts of credit access, and the potential for debt traps or other delayed realizations of borrowing costs. The study also notes that the results may not apply to all markets, and that the external validity of the findings is uncertain. The study concludes that the findings are important for both policy and practice, and that the results suggest a role for welfare-improving interventions in consumer credit markets.