Women drop out of corporate culture at an average age of 38, leading to a "talent drain" from companies in the investment industry, Addidi Wealth's Anna Sofat told delegates at the inaugural Women in Investment Festival in a session on 'The Sticky Middle'.
Speaking at the event at The Brewery in London on 3 March, Sofat said that while women now have "financial clout", that "sticky middle to the C-suite is the problem", adding that the asset management industry is "one of the worst".
"Women tend to drop out of corporate culture around about the age of 38 whether they have children or not. That is us opting out because we don't like what we see there," she said.
She referred to research, which showed that three in four women and two in five men say workplace culture stalls women's careers.
Sofat said: "We all know it is not lack of talent or ambition. We know diverse teams perform better, but it boils down to culture and that sticky middle."
But she said not many women are dropping out to leave working life entirely.
"Some are going elsewhere, some are going to set up their own businesses. Not many are giving up work completely," she said.
"There is a talent drain in big corporates in our industry in particular."
A study by Harvard Business School identified that a key issue is the 24/7 culture - "that is the killer for women", Sofat explained.
Answering emails at all hours is not conducive to the promotion of women and some men, while also acknowledging that there are "layers of behaviours and practices within businesses that are incredibly difficult to change".
"Businesses are going to have to move away from this 24/7 culture. It is just not sustainable for men or women," Sofat told delegates.
When asked what the solution was, Sofat said to be upfront about having a family, or at the other end, caring for older members of family.
"We have the legislation to back us. So put our foot down and demand it."
Delegates at the Festival also heard from Sofat about the 'Are you in?' movement that she launched last year.
According to the website, the movement is about "transforming the financial sector into a profession we can all be proud of - an industry that is inclusive, transparent and improves the wellbeing of everyone".
The five pledges include a commitment to being a beacon for good practice and good behaviour in the industry, and speaking up for people who are not being heard or seen.
Sofat said to delegates: "Imagine a financial services industry that is as caring as the NHS, as clever as Nasa, as colourful as the Pride movement… and we collaborated like a Formula One team.
"If we started to think like teams and collaborated, then we will be that change we want to see."