It is widely recognized that the Bank of Japan’s Exchange-Traded Fund (ETF) purchases had a substantial impact on stock prices. Market participants and media reports have often highlighted that the policy distorted market valuations. At the same time, they pointed out that ETF management appeared to accelerate stock lending activity as the number of ETFs held by the Bank of Japan increased over time. This pattern suggests that the stock market, particularly the lending market, has mechanisms that enhance market efficiency and counteract the effects of the Bank of Japan’s policy.