One of the most iconic symbols in the world of investing is the charging bull on Wall Street. 

Originally guerilla art, installed in 1989 by Arturo Di Modica, the popularity of the 3,200 kg bronze sculpture led to it being a permanent feature.

Now it has a companion.

Overnight, State Street Global Advisors installed a bronze sculpture by artist Kristen Visbal of a young girl facing the Wall Street Bull.

It has been installed on International Women's Day as part of an effort to call on the 3,500 companies it invests in to increase the number of women directors.

As things stand, women hold fewer than 20% of corporate board seats within S&P 500 companies. 

Here in the UK, only 25% of directors of FTSE 100 boards are women. This is its lowest level since 2011.

Activist investors such as State Street could help to move this position towards equality.

It's no secret that companies with more women on the board tend to perform better than those with all male boards, or a higher proportion of male executives.