More than three-fifths (62%) of small businesses are not earning any interest on their business savings, according to research.
A survey by Aldermore found that returns are low even among those who do gain some interest, with 53% earning less than £300, and 26% earning less than £100 a year.
While business owners cited financial pressures and low interest rates as the main reasons for this issue, the research suggested a lack of shopping around could also be holding SMEs back.
Almost two thirds (65%) of SME owners hold business savings with same provider as their personal savings, regardless of the rate.
Ewan Edwards, head of savings at Aldermore, warned that by taking the "easiest" option for their savings, business owners could be missing out on better products.
"Being a business owner comes with a whole host of challenges, so it is vital that business owners make their surplus cash work harder to provide additional financial support and to strengthen financial resilience.
"Over 3 million businesses could be missing out on additional income that would be an added boost when dealing with the multiple financial pressures of running a business; such as cash flow."
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