The study, carried out by research firm Kantar TNS, showed that combined, British millennial and generation X women (those aged between 21 and 53) hold £14.3bn of investments – compared with a total of £29.3bn among men of the same age.
The gap was partially attributed to “unconscious barriers” and embarrassment over a perceived lack of knowledge that could stifle female participation in investments.
The language and jargon used within the investment sector was also identified as potentially off-putting.
Alice Moss, managing director for qualitative research at Kantar TNS, said: “We wanted to understand the root cause behind the huge gap in investment levels and found that a complex web of practical, emotional and unconscious barriers is inhibiting women’s participation in the sector.
“We found that there is a fundamental difference between women and men’s levels of self-esteem and financial autonomy.
“Women can feel embarrassed about their perceived lack of knowledge of the subject and talk about it less frequently with their peers; they also have less connection with the language and marketing used by financial organisations, and have too many other priorities which push investing off their list.
“They’re also not helped by the fact that the sector has been slower than other industries in connecting with a female audience, boosting their self-esteem and reassuring them that they will not be judged.”
The research, which polled 1,220 men and 1,276 women in the third quarter of this year, found that financial autonomy contributes more to men’s self-esteem than women’s – and with men more likely to say they have above average levels of self-esteem than their female counterparts (38% vs 20%).
The findings also showed that women were “considerably less financially engaged” than their male peers, with just 26% of millennial women considering themselves to have a high level of financial engagement, compared with 55% of men.
The picture barely changed with advancing age.
Ms Moss added: “Women have more than 80% of the financial power over everyday spending, which makes this disconnect between financial services brands and the way that they are resonating with women something that the industry needs to address.
“We know that women with higher self-esteem show greater levels of financial autonomy.
“In fact, moving women up just one confidence decile could be worth £12.4bn for millennials and £24.4bn for generation X females – so it’s surprising to see so many providers continuing to miss the mark.
“The traditional approach that investment brands are taking obviously isn’t working for women.”