Nearly half of all variable rate savings accounts in the UK pay interest of 0.5% or less, financial information service Moneyfacts has said.
Of these accounts, nearly half pay 0.1% or less, with many providers having cut rates in recent months.
The Bank of England's Monetary Policy Committee held the Bank rate at 0.5% today for an eighth successive month.
One in 10 savings accounts have cut rates since March although 3.5% increased rates, Moneyfacts said.
Michelle Slade of Moneyfacts said that savers were already experiencing some of the lowest rates ever.
She suggested that providers had lowered rates ahead of new regulations, which came into force at the start of November, that mean providers must give two months' notice before they cut interest rates.
"It is savers, such as pensioners, who rely on the income from their savings to supplement their income who end up worse off," she said.
"Savers will be asking how providers can justify cutting rates further, when the bank base rate has remained on hold."
However, the continued low Bank rate creates a rosy picture for those with a home loan, especially the 58% of existing mortgage holders who are on variable rate deals.
The Council of Mortgage Lenders (CML) said that the average outstanding mortgage rate in September was 3.58%, compared with 5.81% a year earlier.
The lenders' body said that this September the average monthly payment on a £110,000 repayment mortgage at 3.58% was £561. For an interest-only mortgage at the same value it was £328.
This was much cheaper than a year earlier, when the cost, at a rate of 5.81%, was £704 a month for a repayment mortgage, and £533 for an interest-only mortgage.
Last month, the CML said an extra 100,000 people every month were gaining from a drop in their mortgage bills as interest rates remained low.
Borrowers who come to the end of two or three-year fixed-rate deals each month typically have moved to much lower standard variable rates. The CML said that 42% of existing mortgage-holders are still on fixed-rate deals.
A number of mortgage providers have cut rates slightly for new fixed-rate deals in recent weeks.