A major milestone in board diversity has been reached with the majority of Singapore-listed companies now having at least one female director for the first time.

The Diversity Action Committee (DAC) noted yesterday that the proportion of all-male boards had slipped to 49 per cent as of June 30, the first time the measurement has fallen below 50 per cent.

All-male boards and boards with at least one woman director were evenly split as of Dec 31 last year.

Women were steadily increasing their board representation in the first half of this year, occupying 11.2 per cent of board seats on listed companies as of June 30, up from 10.8 per cent six months earlier and 10.3 per cent a year earlier.

But gender diversity is still below the target of 20 per cent female participation by 2020 set by DAC, an advocacy group comprising prominent members of the Singapore business community. That target steps up to 25 per cent by 2025 and 30 per cent by 2030.

The DAC has focused on getting larger firms to lead the way and it has found some success. Women held 14.7 per cent of boards seats among the 100 largest companies by market value as of June 30, up from 13.1 per cent on Dec 31 and 12.2 per cent on June 30 last year. Just 27 of the 100 largest had all-male boards, against 32 six months earlier.

"If the pace is sustained, the top 100 companies will be the first group of companies to achieve DAC's first-tier target of 20 per cent women on boards by 2020, leading the way for other companies to join in," said DAC chairman and Singapore Exchange chief executive Loh Boon Chye in a statement.

11.2% Proportion of board seats occupied by women as of June 30. 49% Proportion of all-male boards as of June 30.

The latest numbers suggest that companies are making an effort to find women to fill board seats and not simply appointing friends and family members of insiders. The proportion of women among independent directors in the top 100 rose to 16.1 per cent as of June 30, from 14.3 per cent on Dec 31 and 12.6 per cent a year earlier.

Regulatory tweaks could support a faster pace of change. Proposed changes to the Code of Corporate Governance will include a requirement that firms set targets on board diversity and report on their progress. A proposal for a nine-year term limit for independent directors could also create vacancies that could be filled by women.

The DAC said 101 independent directors at 48 of the top 100 firms have served at least nine years. Half of all the listed companies have at least one independent director who has served at least nine years.