擔保品限制與生產資源配置：競爭性與獨占性借貸市場之比較

Collateral Constraints and Resource Allocation: A Comparison between Competitive and Monopolistic Credit Markets

本文結合企業受擔保條件限制的融資問題與生產資源配置的決策問題進行討論，分別就訊息不對稱下的競爭性與獨占性借貸市場，探討最適借貸契約的決定以及擔保品設定限制對資源配置是否扭曲。假設生產所使用的兩種資源，只有一般資本可被接受為擔保品，另一種特定資本無法充當擔保品。在訊息不對稱下，競爭性借貸市場中擔保品可作為低風險借款者示訊的工具；當擔保品數量限制產生約制效果時，會導致生產資源配置偏離最適比例，總要素生產力下降。在獨占性借貸市場中，最適契約的擔保品數量為零，擔保品無篩選借款者風險高低的功能，亦不會影響資源配置的最適比例。然由於誘因一致性契約不存在，經濟可能會出現低度投資的現象。

This paper studies the determination of the optimal loan contracts and resource allocation in both competitive and monopolistic credit markets with asymmetric information. It focuses on an economy with risky investment projects that require two goods as inputs, only one of which is accepted by lenders as collateral. Results show that in a competitive credit market, low-risk entrepreneurs tend to choose contracts with a combination of more collateral and lower rates of interest. Under the circumstance that low-risk entrepreneurs face a binding collateral constraint, problems of inefficient resource allocation and over-borrowing arise. On the contrary, the optimal loan contract does not require any collateral in a monopolistic credit market. Although this does not result in production inefficiency, it is possible that high-risk entrepreneurs may not be financed, leading to a problem of under investment in the economy.