LONDON (Reuters) - New York easily remains the world's top financial centre, cementing its position for the past six years after it overtook London, in second place ever since, ahead of Singapore, the latest Z/Yen rankings of global financial centres showed on Thursday.

Hong Kong remains in fourth place, followed by San Francisco nipping at its heels, helped by its strong role in financing tech.

"The leading financial centres improved or maintained their ranking in Global Financial Centres Index 35, with a high degree of stability in the rankings," said Michael Mainelli, the ceremonial Lord Mayor of the City of London financial district, on sabbatical from being chairman of Z/Yen.

New York overtook London in 2018, after Britain voted to leave the European Union two years earlier, which raised questions about London's ability to remain globally competitive.

Brexit triggered a welter of British financial reforms that have yet to stop a flow of UK companies like chip designer Arm seeking listings in New York.

The survey rates 121 financial centres by combining 48,365 assessments, with 8,494 from financial professionals, along with quantitative data from the World Bank, OECD, U.N. and others.

"Continuing professional development has been identified as the most important strategy in ensuring the future strength of talent in the financial sector," Z/Yen said.

In fintech, New York retains its leading position, followed by London, then San Francisco. Shenzhen remains in fourth place, and Washington D.C. moved ahead to fifth, overtaking Singapore, it added.

Seoul joined the top 10 fintech centres, replacing Beijing which has slipped to 11th position.