Applying order-level data, this paper examines the impact of reduction in the minimum tick sizes on price clustering and market liquidity in the Taiwan Stock Exchange. After the reduction, we observe an abnormally high frequency of integer prices through which the tick size generates a negative indirect effect on the bid-ask spreads. After explicitly controlling for this indirect effect, smaller tick sizes indeed reduce bid-ask spreads, but the total effect diminishes. As to the market depth, despite the falling liquidity on the limit order book proxied by the cumulative depth, some traders still switch from non-marketable to marketable limit orders. Overall, the effective spreads are found improved after the reduction, especially for high-volume stocks.