ISA allowances for the next financial year could be as high as £10,680 as savers benefit from a Retail Price Index (RPI)-linked increase.
In March, as part of the last Labour government's Budget, Alistair Darling linked increases in cash and share ISA limits with RPI from April 2011.
Historically, HMRC uses September's figures to calculate the following year's limits. RPI was announced today as 4.6%, putting 2011/12 ISA limits on course for around a £480 increase from the current £10,200.
"The September inflation figure is used for a variety of increases to allowances and benefits, including ISAs", says Informed Choice's managing director Martin Bamford.
"If HMRC is generous and rounds up then the new limit will be £10,680. If it rounds down it will be more like £10,669. The increase will be a round number, easily divisible by 120, so the effective monthly limit does not become too complicated."
However, this month's RPI is lower than the two previous months. For the year to August it was 4.7%, and 4.8% for the year to July.
But Bamford says any increase has a direct and positive impact on savings.
"Looking at the latest ISA sales figures from the IMA, it is easy to conclude that the higher allowances introduced last October have done the trick."
From 6 October 2009, investors over age 50 by the end of the 2009/10 tax year saw their ISA allowance increase from £7,200 to £10,200.
Everyone received the new higher £10,200 ISA allowance from the start of the 2010/11 tax year on 6 April 2010.
Up to half of this allowance (£5,100) can go into a cash ISA. The balance of the unused allowance, up to £10,200, can go into an investment ISA.
Joe McDonnell joins as head of portfolio solutions (EMEA)
Fidelity Multi Asset CIO's outlook
Willis Owen report
From 1 March
More than 16,100 clients compensated