The British banking sector had many small banks in the mid-nineteenth century. From around 1885 until the end of World War One there was a process of increasingly larger mergers between banks. By the end of the merger wave the English and Welsh market was highly concentrated, with only five major banks. News of a merger brought a persistent rise in the share prices of both the acquiring and the target bank (roughly 1% and 7%, respectively). Non-merging banks, especially those whose local market concentration rose because of the merger, saw their stock prices rise. Our findings suggest that the process of bank consolidation increased collusive behavior among merged banks, to the likely detriment of the consumer.

19 世纪中叶，英国银行业拥有许多小型银行。从大约 1885 年到第一次世界大战结束，银行之间的合并规模越来越大。到合并浪潮结束时，英格兰和威尔士市场高度集中，只有五家主要银行。合并消息使收购银行和目标银行的股价持续上涨（分别约为 1% 和 7%）。非并购银行，尤其是那些因并购而本地市场集中度上升的银行，股价上涨。我们的研究结果表明，银行合并过程增加了合并后银行之间的串通行为，从而可能损害消费者利益。