A survey by YouGov for the initiative launched by advice website Boring Money found a "whopping 85 per cent of British women are disengaged with the stock market".
Men were also almost twice as likely to pay into a stocks and shares ISA and outnumber women by seven-to-three on the top ten "DIY" investment platforms.
Holly Mackay, Boring Money founder who has launched the "Ladies Losing Out" campaign said she wants to "address the astonishing gap which remains between men and women when it comes to savings, pensions and investments.
"Women typically live longer and yet save less. We tend to avoid what we perceive to be risky investments but in doing so, are consigning ourselves to a retirement of scrimping and struggling."