Four in 10 (44%) 18 to 40 year olds rarely or never set money aside in case they are ever unable to work, according to research from OneFamily.
Women, renters, those with existing medical conditions and single people were the least likely to be saving any cash, the survey of 2,000 UK adults aged between 18 and 40 found.
But researchers did not extend to the reasons for why people were not saving.
Encouragingly, half of those polled (51%) said they did put money aside in case they are unable to work for a period of time, for example due to illness, injury, or redundancy, but 44% said they rarely or never did.
Looking at the gender divide, more than half of men (56%) were saving for this specific reason, compared to 45% of women.
Similarly 40% of men said they rarely or never did this, compared to 48% of women.
The research further revealed concerning numbers among respondents who had physical or mental health conditions lasting 12 months or more.
Such conditions could easily mean many adults would be unable to work for periods of time, the insurer said, be it in full or part time employment.
However, the majority (53%) said they rarely or never put money aside to help with this, while 41% said they did.
Meanwhile, renters saved significantly less than those who owned their homes.
More than half of homeowners (57%) said they did save to help if they were suddenly out of work, whereas 38% did not. Among renters 45% saved compared to 50% who did not.
Single people were far less likely to regularly or often put money aside compared to those that were married. Only 43% saved for a rainy day compared to 63% of people who were married.
Ryan Griffin, protection director of OneFamily, (pictured) said: “These figures are concerning and show that many young adults in the UK don’t have any form of financial safety net.
“Life is unpredictable – for example you could be made redundant or find you have a health condition that impacts your ability to work, so this is a real risk in terms of financial vulnerability and exposure.
“Putting money aside for such circumstances can seem a big task, especially if finances are already stretched, and it is easy to have the ‘it won’t happen to me’ view.
“However, a few pounds a month can make a big difference in the long run, whether you put it in a savings account or buy a product that protects your income.
“Unemployment rates are sitting at a four-year high, so it’s really important to have a nest egg put aside for emergencies and to protect yourself, as we never know what is around the corner.”