In recent weeks, both Ms. Gillibrand and Mr. Ford have sought to portray themselves as allies of the financial industry, even as they acknowledge public outrage over extravagant executive compensation deals.

Mr. Ford, a vice chairman of Merrill Lynch, is promoting himself as unabashedly pro-business, calling for a big reduction in the corporate tax rate and for exempting many businesses from payroll taxes, while Ms. Gillibrand has expressed misgivings about a bank tax proposed by President Obama that is opposed by Wall Street firms.

A friend of Mr. Ford’s who works in finance and contributes to Democratic candidates was surprised to receive a call recently from Ms. Gillibrand, who requested a personal meeting. When this person expressed support for Mr. Ford, Ms. Gillibrand pressed her request anyway, said a person with knowledge of the situation, who spoke on condition of anonymity, for fear of offending the senator.

The competitiveness between Ms. Gillibrand and Mr. Ford in the corridors of New York business became apparent a few weeks ago, when she convened a last-minute meeting of her campaign finance committee at the law firm of Debevoise & Plimpton, whose roster of corporate clients includes Goldman Sachs and JPMorgan Chase.

Mr. Ford had just acknowledged his interest in the Senate seat, and Ms. Gillibrand wanted to rally her biggest fund-raisers. At one point, a member of the committee asked how many of the nearly 80 people in the room had donated to Mr. Ford when he ran for Senate in Tennessee. Half the people in the room raised their hands, according to a participant who attended the meeting.

Ms. Gillibrand was unknown to much of Wall Street a year ago when she was appointed to fill the seat vacated by Hillary Rodham Clinton after she became secretary of state. What some executives did know gave them pause: She twice voted against the federal bailout of banks during the financial crisis.

But Ms. Gillibrand has spent hours on the phone with finance executives, soliciting their views. When Glenn Hutchins, the co-chief executive of Silver Lake, a private equity firm, sent Ms. Gillibrand a 75-page PowerPoint presentation on the causes of the banking meltdown, he was unsure if she would ever read it. She not only did, but she also responded with a long list of follow-up questions. “I was very impressed by that,” he said.