The sector saw a net outflow of £85m in comparison to the same period a year ago when it saw inflows of £710m.
Net Isa sales also saw a net outflow of £305m in January, down from an inflow of £36m in December, the highest outflow since July 2008. The best-selling Isa sector was global emerging markets followed by Asia Pacific excluding Japan.
Net retail sales were down from £1.2bn in December to £567m in January but funds under management were up from £659bn to £688bn.
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The best-selling asset class was equity, for the fifth consecutive month, followed by mixed-asset. UK All Companies was the worst-selling sector with outflows of £354m.
Daniel Godfrey, IMA chief executive, said: "As happens most years, net retail sales were lower in January than in December. One factor was reduced sales of fixed income funds continuing the decline in these sales that we have seen since last summer.
"However, retail investor interest in equity funds was strong for the fifth month in a row, with four equity sectors in the top five selling sector this month."
Adrian Lowcock, senior investment manager at Hargreaves Lansdown, said: "Transfers may account for the fall in Isa sales for January 2013. New rules came into play in January requiring all firms to allow stock transfers from one platform to another. As a result, investors have been freed up to move their stock to the platform of their choice. January's figures may be a one-off as investors took advantage of these changes."

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