More than £340m was invested in the first five days of April 2013 alone, higher than any monthly sales recorded in the last 11 months, according to statistics from the Investment Management Association (IMA).

Mixed Asset funds were the best-selling in March 2013 with net sales of £291m – the first time this asset class has been the best-seller since July 2011 when it achieved net retail sales of £437m.

Equity was the next best-selling asset class with net sales of £105m, the lowest since August 2012. Equity funds had previously been the best-selling for six consecutive months.

Bond funds were also popular with sales of £36m, following two consecutive months of outflows in 2013.

Daniel Godfrey, IMA chief executive, said: “The last minute rush into ISAs at the end of the tax year appeared again with £347m invested in the first five days of April alone. This is a common trend, but investors should be reminded that they can invest in ISAs on a regular monthly basis. This not only reduces the financial burden of finding a lump sum but also reduces risk as you buy more units if prices fall, which then achieve higher proportionate gains when prices recover.”