Fund platforms have reported their highest gross Isa sales on record, according to the Investment Management Association.

The monthly fund statistics, published this week, revealed fund managers sold £1.3bn worth of Isas. The net retail sales for April were £2.4bn, half of which were sales of Isas.

Some £349m was invested in Isas within the first five days of the month which was the end of 2010/11 tax year.

A further £877m was invested from 6-30 April as clients got in early with their Isa investments.

This sum brings the funds under management for Isas to £109bn and the total funds under management to £594.6bn.

Total funds under management for fund platforms were £112bn.

Richard Saunders, chief executive of the IMA, said: “April’s statistics reflect a strong 2011 Isa season with Isas accounting for about half of the £2.4bn investors added to their holdings.”

The highest selling sector was the £ Strategic Bond, for the fourth month running, with net retail sales of £465m in April.

This is double the monthly average of £206m for the previous 12 months.

The £ Strategic Bonds are funds which invest at least 80 per cent of their assets in sterling dominated fixed interest securities.

Mr Saunders said: “Investors continue to favour strategic bond funds. For the fourth month running, the £ Strategic Bond sector was the best IMA sector in April, accounting for 39 per cent of gross bond sales.”