Overall, the statistics show less money going into cash ISAs as savers tire of low rates.

Just 18% of women invested their ISA, compared to nearly a quarter of men, but this was up on previous years. Men hold an average of £3,611 more in ISAs than women: men have an average ISA holding of £29,448 and women £25,837.

Laura Suter, personal finance analyst at investment platform AJ Bell, said: “Women are great at saving, and at every age group more females are saving into an ISA than men. The latest figures show that 5,543,000 women subscribed to an ISA account compared to 5,141,000 men in 2016/17, the latest year this breakdown is available for.

“However, for women the bulk of this money is still sitting in cash, rather than being invested. Around 80% of females saved their money into a cash ISA, compared to 72% of men, while 17% of women subscribed to a stocks and shares ISA, compared to 24% of men. The rest did a combination of the two.

Low returns

“Females also have less money in their ISA account, thanks to getting lower returns on their money as they are sitting in cash while interest rates are at rock bottom, rather than investing it. The top paying easy-access cash ISA at the moment is paying 1.46%, which is lower than the current rate of inflation, meaning that it is losing money in real terms.”

Nevertheless, Suter said the higher take-up of stocks and shares Isas among women this year was ‘encouraging’.

Rachael Griffin, Quilter tax and financial planning expert, said savers were punishing the low rates on cash offered by banks and building societies: “The number of people putting money into stocks and shares Isas increased by nearly a quarter of a million last year. Although cash Isas are still dominant, their share of all Isa subscriptions fell to 72% as a result.

“Although subscription numbers declined slightly, the amount saved actually increased on aggregate because, on average, the typical stocks and shares Isa investor is putting more money into their account. The average amount paid into an Isa increased by 15% to nearly £6,500, although this still means the average Isa holder has around £13,500 of unused Isa allowance each year.”

High earners

The figures showed 57% of people earning £100,000-£149,999 and 39% of those earning over £150,000 didn’t take advantage of their full ISA allowance in 2016/17. Sarah Coles, personal finance analyst at Hargreaves Lansdown, said: “Higher earners put more into their ISAs, but most people earning under £150,000 don’t take advantage of their full ISA allowance – and 39% of those earning over this level don’t either. If you’re a higher earner, you’ll be paying tax at eye-watering rates, so it’s well worth revisiting whether you can take more advantage of tax-efficient savings and investments in order to hang onto more of your money.”