Of course, there are other centres that operate on a global scale in certain sectors but nowhere else offers the breadth and depth of world-class services that London and New York do.
As such, it is naturally assumed that these two cities are fierce competitors and, in the sense that every financial centre has to operate in an increasingly competitive global marketplace, this is true.
However, the relationship between London and New York is also one of shared interests and mutual co-dependence.
It is not an either-or situation, firms do not want to be based in one or the other; they want access to both.
In addition to political pressures borne out of the recent financial crisis, there is one overriding concern that unites both London and New York - the shift of the global marketplace towards the East.
Financial centres in Asia are growing rapidly and are desperate to attract the top global firms that have traditionally been based in London and-or New York.
These centres have many advantages, not least with regards to property, planning and infrastructure.
It is much easier to meet the needs of the international business community - be it for a million square feet of office space or for an efficient, high-capacity transport system - in a brand-new business environment than it is to fit such projects around a medieval street network.
One of the key messages to come out of today's panel discussion, "London, New York: two cities joined by a common vision", in the London Pavilion was that both London and New York need continued investment in property and infrastructure to compete in the global marketplace in the years to come.
We can only succeed in achieving our shared ambitions if we continue to work together, drawing on the experience that makes these two cities the world's leading financial centres.
Stuart Fraser is the policy chairman at the City of London