Individual savings accounts recorded their best sales in nine years in the run-up to the end of the financial year, according to the Investment Management Association.
The IMA says the period between March 1 to April 5 brought in £956m in Isa sales.
For the wider 2010/11 tax year, Isa sales of £3.7bn were recorded, the second-best haul in 10 years.
Isas make up 18 per cent of all authorised funds under management, which totalled £106.4bn at the end of March.
Overall in March, UK funds experienced net retail sales of £1.9bn.
The best-selling IMA sector in March was the strategic bond sector, with retail sales of £337m. Global was the second most popular with £287m followed by the cautious managed sector with £255m.
Japan also saw the fifth-highest inflows at £146m, despite its earthquake, tsunami and nuc-lear crisis in the same month.
However, outside Japan, the Asia-Pacific region struggled with outflows of £185m, making it the worst-selling sector despite strong popularity with retail investors in recent years.
Chelsea Financial Services managing director Darius McDermott says: “I am not surprised Japan has done OK as there was a valuation anomaly after the disaster. Markets tend to overreact and this created an opportunity.”