The Hong Kong stock exchange has proposed standardising board lot sizes, reducing the number of trading units from more than 40 to eight options in a bid to boost market efficiency and liquidity. Bourse operator Hong Kong Exchanges and Clearing (HKEX) was proposing to limit the choices listed companies make regarding their trading unit size, or board lot, from one share to a maximum of 10,000 shares, according to a consultation paper published on Thursday. The options in between are: 50, 100, 500, 1,000, ...