Hong Kong’s cozy all-male boards have been put on notice. Rules that could become effective within months will force them to appoint at least one woman director. It’s an overdue change that may go some way to bolstering the city’s dented status as an international financial center.

The territory is an embarrassing laggard in the worldwide trend toward greater gender diversity. The proportion of female directors in Hong Kong companies that are constituents of MSCI’s flagship global equity index grew marginally to 12.7% last year from 12.4% in 2019. Granted, that’s far from the worst in Asia. But the city trails well behind London and New York, the global financial hubs to which it aspires to benchmark itself — and the gap is widening. Last year, 34.3% of directors of U.K. companies on the MSCI ACWI were women; the ratio for the U.S. was 28.2%.

Blame Hong Kong’s clubby world of family-controlled and male-dominated businesses. Close to a third of the city’s 2,500-odd listed companies had no women on the board as of the end of 2020. Many directors hold multiple board seats across different businesses, creating a semiclosed and self-perpetuating world driven by relationships.