Twice a year, Z/Yen releases its Global Financial Centres Index (GFCI), and the latest for September 2017 is just out.

The survey gives cities a combined score based on five main factors:

Business environment

Financial sector development

Infrastructure

Human capital

Reputational and general factors.

There was a huge reaction when New York dethroned London as the world's top financial hub in 2013.

But the British capital regained its crown in 2015 and this year extended its lead despite the UK's looming departure from the European Union.

Check out all the other cities that made the cut:

20. Shenzhen – The Chinese city climbed two places to reach the top 20, scoring highly in the infrastructure category.

19. Boston – The US city tumbled 10 places this year, making it one of the biggest fallers alongside San Francisco.

18. Dubai – Up seven places in the ranking, Dubai was boosted by a strong showing in the reputation category, placing sixth in the world.

17. Vancouver – The Canadian city is the fifth most powerful financial centre in the North American continent, according to the index.

16. San Francisco – Along with most other US-based centres, San Francisco saw a fall in the rankings, down 10 places to 16th.

15. Geneva – Rising five places, Geneva is the fifth-most important European city for finance, and Switzerland's second-most important behind Zurich.

14. Luxembourg – The tiny city-state is Europe's fourth highest-ranked hub, and punches well above its weight in finance.

13. Melbourne – The city rocketed seven places to 13th, and, along with Montreal and Zurich, is seen as one of the most stable financial centres.

12. Montreal – Up two places this year, Montreal is Canada's second highest-ranking financial centre.

11. Frankfurt – The German powerhouse surged up 12 places in the list this year. The city has benefitted both from Brexit and from being the home of the European Central Bank.

10. Beijing – The Chinese capital rises six places after a strong showing in the infrastructure and human capital categories.

9. Zurich – the Swiss city increases its ranking by two places to become the second highest-placed European city on the list

8. Sydney – The Australian city retains its crown as it the highest-ranked city in the southern hemisphere.

7. Toronto – the Canadian city takes the second-highest ranking of any city in the Americas, rising up three places from last year.

6. Shanghai – The Chinese city jumps seven places in the rankings, and was voted the most likely financial centre to become more significant.

5. Tokyo – The Japanese capital remains a global financial centre, coming out fifth overall.

4. Singapore – The city state comes in fourth overall, but took a slight dip of one place, after losing 18 points.

3. Hong Kong – The former British colony takes the highest spot of any Asian city, as both a well-developed financial hub and a gateway to China.

2. New York – The US financial powerhouse dropped 24 points since the last survey, coming in just fourth for reputation.

1. London – the UK capital extends its lead to 24 points over New York, despite concerns about the City's future within the European Union.