A fifth of people in a relationship say their partner does not even know how much they earn, while 19 per cent hide debts.
Lack of trust seems to be a driving force behind many secret finances, the report said. A third of people admit they have no specific plans for their secret income but just do not want their partner to be able to access all their money. Nearly a quarter do not trust their partner to make the right decision about their finances so want to keep control.
Kirsty Anderson, retirement income expert at Prudential, which carried out the research, said: “At any stage of a relationship it is important to have open and honest conversations about finances, but it becomes especially relevant when approaching retirement as decisions made then will impact the rest of your life.”
More than two-fifths of those keeping income secrets say their basic salary is higher than their partner thinks it is, while a quarter have income from an investment that their partner is not aware of.
Around one in ten people said they just wanted to keep some of their money for themselves, while others admitted they were squirreling away savings so that they could be financially independent if they broke up.
Ms Anderson added: “Saving money is always a good idea but doing it so you are protected in the event of a relationship breaking down means missing out on potential tax benefits.”
Savings are not the only financial secret kept by some couples, with a fifth saying they are keeping debts secret from their partner. For the majority, these debts arose from general living costs, but for others the debt was caused by overspending due to previous relationships. Around one in five who had secret debts said they had fallen into the red after a break up, while 10 per cent inherited the debt from a past relationship.