A recording of a speech the then-home secretary gave to Goldman Sachs in May has been published by the Guardian, revealing she had numerous concerns about the impact that leaving the EU would have on businesses.
In an hour-long talk to City bankers on 26 May, she said that the "economic arguments" for remaining in the EU were clear, a somewhat stronger position than she took in public during the referendum campaign.
May said that "one of the issues is that a lot of people will invest here in the UK because it is the UK in Europe".
If we were not in Europe, I think there would be firms and companies who would be looking to say, do they need to develop a mainland Europe presence rather than a UK presence? So I think there are definite benefits for us in economic terms.
She also highlighted the importance of maintaining strong security links and sharing information between countries. During the referendum campaign May generally kept a low profile, and had irritated some senior Conservatives by staying out of the main arguments.
In recent weeks, the government's response to the City's fears over leaving the EU has left some concerned. May has repeatedly said that any Brexit deal would seek to curb immigration, thought to be one of the main reasons why many people opted to leave the EU.
But businesses are concerned at the lack of commitment to remaining in the single market, and are worried about continued access to talent from abroad.
The chancellor, Philip Hammond, has sought to reassure businesses that their concerns over Brexit are being considered, and that the closest possible access to the single market would be sought.
Yesterday he repeated promises that the government would prioritise financial services in upcoming discussions with the EU. He said:
I certainly have been seeking to reassure financial services businesses that we will put their needs at the heart of the negotiation with the European Union.
We understand their needs for market access. We also understand their needs to be able to engage the right skilled people.
Last week the chancellor attempted to calm fears over Brexit after City A.M. reported concerns of Whitehall indifference towards financial services.
Hammond was questioned over our front page by MPs on the Treasury select committee during a two-hour grilling.