<p>This paper examines an e-commerce supply chain consisting of an offline supplier and two competing online retailers. To reduce online operating costs, the supplier selects a platform retailer, a reselling retailer, or both. The reselling retailer, being capital-constrained, can borrow funds from either the platform or a bank to alleviate financial pressure. Subsequently, the reselling retailer sells products on the platform and pays a commission. In an offline supplier-led Stackelberg game, an interesting co-opetition relationship exists between two online retailers regarding sales and financing. This study explores the interactions among channel selection and financing preferences of the three supply chain members. Interestingly, when the supplier or platform favors the single-platform reselling channel, the capital-constrained retailer that exits the supply chain can influence the channel equilibrium through side payments. Our findings reveal that the supplier’s and platform’s channel choices significantly affect the financing preferences of the capital-constrained retailer. In a single channel, the platform prefers providing financing only at high commission rates. In a hybrid channel, financing preferences depend on factors such as the commission rate, substitution intensity, and interest rates. Counterintuitively, when the substitution intensity is high, the capital-constrained retailer prefers platform financing (PF), even if the platform’s interest rate exceeds the bank’s interest rate under the hybrid channel. This is because PF softens horizontal price competition between the capital-constrained retailer and the platform retailer.</p>