Sadiq Khan needs to promote London's Fintech industry more, according to industry experts Trusek.
The calls come after a list of 23 technology startups, due to join the Mayor of London on a visit to the USA, was released.
Steven Hatton, Co Founder and Director of Trusek, said: "Mayor Khan will be taking 23 technology companies, only 2 of which are related to the Financial Services industry.
"Given that the Deputy Mayor of London for Business is Fintech entrepreneur Rajesh Agrawal, the industry would expect to see a much more Fintech-friendly start to his term of office."
The delegation, which will include Deputy Mayor Agrawal, Sadiq Khan and these 23 startups, will travel between Chicago and New York, with the aim of securing more investment, expansion and export opportunities in the United States.
The US has been highlighted by the mayor's promotional company, London & Partners, as Britain's most valuable trading partner.
Indeed, figures revealed for April of this year found that the US accounted for £4.4bn of UK exports.
It is believed that almost 600 US firms entered the City over the decade prior to 2015, resulting in over 16,000 jobs being created.
But the City has been hit by Brexit, and data revealed recently shows that London tech firms have received over $500 million since the vote on 23 June? to plug possible gaps.
Mr Hatton said: "The vote to leave the EU has cast doubt into the UK's financial services industry. We need proactive policies from all of our elected officials that will ensure the industry thrives through Brexit."
The trade mission shows a continuation in policies from Boris Johnson's mayoralty, which included an International Business Programme. The aim of the programme, which began in February, is to drive global growth for 800 London SMEs over the next three years.
Mr Hatton added: "The visit will take place next month, and I hope that the Mayor will seek more representation from the FinTech industry before the visit."
