Using micro-level data on the entire population of business loans of a bank-based economy, we empirically test some of the core predictions of the SME financing literature, examining banks’ lending specializations in firm size and lending technologies. Rejecting the conventional belief that smaller banks focus more on relationship loans than do larger banks, we find that banks of different sizes dedicate similar proportions of loans to relationship lending. However, supporting the SME finance theories on the organizational advantages of small banks, we find that smaller banks provide more access to relationship loans to small firms, though such loans are usually more expensive.