中国銀行業の経営構造 : 確率的費用関数による4大国有銀行と株式制商業銀行の比較分析

中国企業の資金調達の7割は銀行からの融資で、その大部分を4大国有銀行が占めていると言われる。定性的な研究では、その4大銀行は、その他の株式制商業銀行と、所有構造や事業内容が異なるものだと指摘されてきた。しかしながら、従来の実証研究では、4大銀行と株式制銀行を同一の種類の金融機関と捉えて分析してきており、定性的研究成果を反映していない不適切な計量分析となっている。そこで本稿では、トランス＝ログ型の確率的費用関数を用いて中国銀行業の費用構造を分析し、次のような両者の相違を明らかにした。①4大銀行と株式制銀行は異なる費用関数を持つ。②4大銀行は、人件費・物件費への依存が少ない。③株式制銀行は規模不経済。④近年は4大銀行はコスト増加傾向にある。本稿の推計結果は、4大銀行と株式制銀行が明確に異なる種類の金融機関であることを示すものであり、先行研究の計量分析の前提条件に疑問を投げかけるものである。, It is said that the main source of financing for firms in China are bank loans and the large state-owned commercial banks (SCBs) account for nearly seventy percent share of that market. SCBs have a number of non-performing loans, while which dominate the China bank market. They therefore need to improve their management. One of the most important issues of the Chinese financial system is banking sector reform, which means to make SCBs behavior change. Many studies about this topic have been done with qualitative and quantitative methods. Econometricians also have focused on that; Chi, Sun & Lu(2005), Fu & Heffernan (2007), Berger, Hasan & Zhou (2007) and Matthews, Guo & Zhang (2007) studied the efficiency of banks in China, and Yuan(2006) measured the competitiveness of the Chinese bank market. Those studies assumed that SCBs and joint stock commercial banks (JSCBs), which means non-SCBs commercial banks, have the same cost function except efficiency, though qualitative studies pointed out that the histories and initial business of SCBs and JSCBs differed from each other and their objective and business are not the same. It is possible that current econometric studies about the Chinese banks don’t reflect qualitative studies and that their assumptions are inappropriate. In addition to that, former studies didn’t analyze the basic features of the Chinese bank market like such as the scale and scope economy as far as we know. In this study, we investigated the features of SCBs and JSCBs by estimating the cost functions of them and measuring the structure of the cost-share, the scale economy and the scope economy. We have cleared that SCBs and JSCBs have different cost functions to each other, which suggests that they cannot be studied as if they are the same kind of financial institution. In short, our analysis suggests that former econometric studies had the wrong presupposition. In addition, recent reforms of SCBs have not been enough in that SCBs are different to JSCBs, which seem to be maximizing their profits.