Knight Frank has done a deal targeting super-rich purchasers with the largest estate agency in the United States.

The new alliance, between Douglas Elliman Real Estate and Knight Frank Residential, will result in joint marketing and the co-branding of seven offices in New York, Florida and Los Angeles.

The combined network results in 400 offices in 52 countries and nearly 20,000 agents.

The two firms between them will jointly market property on sale at $1.5m (£1.16m) or more.

Lord Andrew Hay, global head of Knight Frank Residential, said: “The property market has become increasingly global as the mobility of buyers increases.

“For agents, this trend dictates that it is essential to be best in class in both New York and London in order to provide high net worth clients with the most comprehensive service and access to the best properties globally.

“The aim of the alliance is to provide a single market view, consistent expert advice and exceptional service – whether it be in Park Lane or Park Avenue.”

According to Knight Frank’s latest Wealth Report, the number of ultra high net worth individuals in the world is set to rise from 168,000 over the next decade to 215,000.

The new alliance will capitalise on this expansion, with the prevailing trend for the super-rich to own property in London and New York.