London ranks fifth in a table of cities with the highest percentage of millionaires per head of the population.
The UK capital has moved from sixth place, with 3.4% of the population now millionaires.
Monaco topped the list, with almost a third of its population (31.1%) classed as millionaires, a 1.9% increase from 2014.
Zurich and Geneva follow in second and third place with millionaires making up 24.3% and 17.7% of the respective populations.
In fourth place is New York, with almost one in 21 of the city’s residents classed as millionaires (4.7%).
Oslo (2.9%), Hong Kong (2.7%), Frankfurt (2.7%), Singapore (2.7%) and Amsterdam (2.7%) round off the top ten.
Political stability is another prerequisite for a large millionaire density which explains the current findings
Oliver Williams of WealthInsight
“It’s unsurprising to see that Monaco is the most likely place where you will bump into a millionaire; the principalities’ low tax and Mediterranean waterfront is the ideal habitat for wealthy individuals,” Oliver Williams of WealthInsight said.
“Favourable tax and quality of life are the two criteria for large millionaire densities in most of these cities. Switzerland’s two financial hubs of Zurich and Geneva offer both these allures.
“London is one of the world’s largest tax havens for overseas millionaires and, at the same time, it is indisputably one of the foremost financial capitals of the world.
"Political stability is another prerequisite for a large millionaire density which explains the current findings," he added.
A separate survey by WealthInsight in May revealed that London has more multi-millionaires living in the city than any other city in the world.
The research found that London's multi-millionaire population increased by 0.8% from 2014 to 2015.
The city now has 25% more multi-millionaires than its closest rival Tokyo.
Two other UK cities made the top 100 with Birmingham ranking in 65th place with 138 multi-millionaires living in the city and Edinburgh at 74th with 112 multi-millionaires.
Williams commented, "For the three years that we have run this survey, London has maintained the lead with the largest population of multimillionaires. Though the growth in London's wealthy residents has slowed from 3.3% last year to 0.8% this year, the capital looks set to maintain its edge over rivals such as Tokyo and Paris, whose economies have made them less attractive to multimillionaires.
"For the next two to three years at least we should expect London to retain its lead as the global capital of multimillionaires."