LONDON -- In the City of London, there are just four women running companies in the FTSE 100, and three of them are American.

That's just 4% of companies with female CEOs. In fact, less than 7% of all FTSE 100 executive directors are women, according to figures from Boardwatch. The numbers are better when nonexecutive directorships are included. Overall, 17% of directors are female, with women comprising one in five of nonexecutives.

There is only one female chairperson, Alison Carnwath of Land Securities.

The move toward diversity
Last year the Davis Report set a target for 25% of FTSE 100 directors to be women by 2015. To get there, Lord Davies calculated that around a third of new directorships should go to women in each of the intervening years. Roughly speaking, that program is on track. But though it makes for a more respectable representation of women on company boards, it is still remarkable how few there are in executive posts.

Who are the four, and what companies do they run?

High Street heavyweight
Angela Ahrends is an American who carved out her career in the fashion industry in New York. She became CEO of luxury-goods retailer Burberry (LSE: BRBY.L) in 2006. Turnover has more than doubled in that time, and the shares have risen 150%.

This week, Burberry stock dropped 20% after a profits warning. The suggestion that status-conscious Chinese might be reining back spending reverberated across the whole luxury-goods sector. But even after a 20% drop, the shares still trade on a price-to-earnings ratio of 23, reflecting the market's belief in the long-term growth story.

Mining magnate
Cynthia Carroll is less secure at miner Anglo-American (LSE: AAL.L). According to the Daily Telegraph, several big investors have lobbied for her to be replaced. Since she became CEO in March 2007, the shares have dropped 30%, underperforming rivals Rio Tinto and BHP.

A recent 50% drop in interim earnings did not help her cause. But her efforts to diversify Anglo's business away from South Africa have been dogged by problems. The huge Minas Rio Brazilian iron ore project has suffered delays and cost escalation, and the company was forced to sell a 25% stake in its Chilean copper mine to the state-owned producer after spending billions of dollars developing it. Nevertheless, she takes credit for restructuring the company that had sprawling and costly operations before her arrival.

Some pundits think Anglo may be vulnerable to an opportunistic bid.

Media mogul
The third American is Marjorie Scardino of media group Pearson (LSE: PSON.L). In 1997, she was the first woman to be appointed an FTSE 100 chief executive. The group has been transformed in that time, although the shares are pretty much back where they started.

The business mix of education, business information, and publishing -- including the Financial Times group and Penguin -- is now more heavily skewed toward the education sector. The company's strategic challenge is to secure its position in digital content, which represents nearly a third of sales.

Tobacco tycoon
It is perhaps the Brit among the four, Alison Cooper, who can sleep most peacefully at night. As CEO of Imperial Tobacco (LSE: IMT.L) since 2010, she runs a company in one of the most defensive sectors, where the degree of global consolidation is such that any thoughts of a takeover bid might well be squashed by competition authorities.

The tobacco industry faces challenges from health legislation and counterfeiting, but time and again it has proved resilient. That's one reason why it forms a core holding of leading U.K. dividend stock-picker Neil Woodford. You can find more about his favorite blue chips in this free Motley Fool report: "8 Shares Held By Britain's Super Investor." You can download the report here.

These female CEOs run very different businesses in diverse sectors, and, by and large, they've been successful. Perhaps there should be more of them.

Investing is by no means easy in today's uncertain economy. That's why we've published "Top Sectors for 2012" -- our guide to three attractive industries. This free report will be dispatched immediately to your inbox.

More investment opportunities: