This study investigates the role of passive investors in the equity lending market by utilizing the expansion of exchange-traded fund (ETF) markets due to the Bank of Japan’s (BOJ) ETF purchasing program. We find that the BOJ’s purchases increase equity prices particularly for stocks with limited availability in the equity lending market. However, over the longer term, the BOJ’s cumulative purchases reduce lending fees, thus weakening the program’s effects. These findings suggest that ETF managers supply stocks that constitute ETFs to the equity lending market, and the lending behavior of ETFs, influenced by the BOJ’s program, alleviates short-selling constraints.

We investigate the effects of the Bank of Japan’s (BOJ’s) exchange-traded fund (ETF) purchase program on equity risk premia. Utilizing the cross-sectional variations in the amount of individual stock that the BOJ has indirectly purchased in the program, the empirical analysis reveals that: (i) the BOJ’s ETF purchases instantaneously support stock prices on purchase, and (ii) the positive effects on stock prices, combined with the countercyclical nature of the BOJ’s purchases, affect the market beta and coskewness of Japanese stocks, leading to an economically significant decline in risk premia. • Countercyclical BOJ purchases lower Japanese equity risk premia. • BOJ’s ETF program reduces market beta and coskewness of stocks. • Decline in risk premia significantly boosts Japanese stock prices. • Panel data reveal cross-sectional effects of BOJ’s ETF purchases.