Why is the financing rate measurably above the risk-free rate? My understanding is that the box spread replaces bank or broker loan or deposit interest (who make a profit from the spread between interest paid and interest received). The box spread is arm’s length, i.e. cuts out the middle man. Retail investors and institutions both use the same options market. Shouldn’t the implied rates of any options combination be close to the risk-free rate? If I buy the box instead of selling it, can I make ca. 0.5% above the risk-free rate?