The European financial industry spends more than €120m per year on lobbying in Brussels and employs more than 1,700 workers to "influence" European Union policy making.
According to a report from campaign group the Corporate Europe Observatory (CEO), the financial industry commands "tremendous" lobbying resources and enjoys "privileged access" to decision makers.
"The crisis revealed a clear need for stronger rules on financial markets," said Kenneth Haar, a CEO team member.
"But reform has proved difficult, and these numbers are an important part of the explanation."
He added: "The financial lobby's fire power to resist reform has been evident in all significant battles over financial regulation since the collapse of Lehman Brothers."
The research also claimed that the financial sector lobbies EU decision-makers via more than 700 organisations, including companies' public relations offices, business associations, and consultancies.