ABSTRACT: BACKGROUND:In addition to payments for services, anesthesia groups in the United States often receive revenue from direct hospital payments. Understanding the magnitude of these payments and their association with the hospitals' payer mixes has important policy implications. METHODS:Using a dataset of financial reports from 240 nonacademic California hospitals between 2002 and 2014, the authors characterized the prevalence and magnitude of direct hospital payments to anesthesia groups, and analyzed the association between these payments and the fraction of anesthesia revenue derived from public payers (e.g., Medicaid). RESULTS:Of hospitals analyzed, 69% (124 of 180) made direct payments to an anesthesia group in 2014, compared to 52% (76 of 147) in 2002; the median payment increased from $242,351 (mean, $578,322; interquartile range, $72,753 to $523,861; all dollar values in 2018 U.S. dollars) to $765,128 (mean, $1,295,369; interquartile range, $267,006 to $1,503,163) during this time period. After adjusting for relevant covariates, hospitals where public insurers accounted for a larger fraction of anesthesia revenues were more likely to make direct payments to anesthesia groups (? = 0.45; 95% CI, 0.10 to 0.81; P = 0.013), so that a 10-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 4.5-percentage point increase in the probability of receiving any payment. Among hospitals making payments, our results (? = 2.10; 95% CI, 0.74 to 3.45; P = 0.003) suggest that a 1-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 2% relative increase in the amount paid. CONCLUSIONS:Direct payments from hospitals are becoming a larger financial consideration for anesthesia groups in California serving nonacademic hospitals, and are larger for groups working at hospitals serving publicly insured patients.