Top of the pile without any doubt has been Japanese equity markets.

The runaway leader over the first four months of the year, the widely-followed Nikkei 225 notched up a 19% return over the first three months of 2013, although it remains well off record highs.

Moves late last year by the Bank of Japan to halt the appreciation of the yen have paid off, and looser monetary policy has helped support Japanese equity markets.

Consequently, a large number of Japanese equity funds feature among the most successful performers in the first quarter of 2013.

Top of the pile is the Legg Mason Japan Equity fund, managed by Hideo Shiozumi, which has returned 45.08% for the three months to the end of March, according to Morningstar.

The manager invests further down the market cap spectrum than his peers, benefiting from a bull run in Japanese small caps. This has led Shiozumi to produce a three-month return substantially ahead of the IMA Japan sector average return of 19.78%.

Four other small-cap Japanese equity mandates also left alll other funds standing.

The Invesco Perpetual Japanese Smaller Companies fund is in second place, returning 35.62% over the first quarter.

Fund manager Osamu Tokuno has cautioned Japanese equity markets are overdue a short-term pause given their strong rally since November, but believes a further bout of aggressive monetary policy and deregulation will be supportive of further upward momentum throughout the year.

AXA Framlington Japan Smaller Companies (34.13%), Baillie Gifford Japan Small Companies (30.46%) and BGF Japan Small & Mid Cap Opportunities (29.3%), complete the top five.

M&G Japan Smaller Companies features just outside the top five, returning 25.32% over the period.

Elsewhere, US equity funds also performed well in a quarter which saw the Dow Jones and S&P 500 hit record highs.

Below is the full list of the top ten performing funds of 2013.

Data from 1/1/2013 to 31/03/2013 Source: Morningstar