SEC commissioner Elisse Walter. (Alex Wong/Getty Images)

Anyone who tracks the Securities and Exchange Commission already knows that President Obama wants New York attorney Mary Jo White to be the agency’s next leader.

But the person currently holding that position has no intention of simply keeping the seat warm until the White House pick gets there. In fact, that’s the reason the word “acting” does not appear before SEC Chairman Elisse Walter’s title, even though she may hold the job for only a few more months.

“I made it clear to everyone that I wasn’t interested in being a caretaker,” Walter said. “I wasn’t going to just switch the lights on in the morning and off at the end of the day. If I was going to be chairman, I was going to be chairman.”

For the White House, Walter was a reliable pick. She had been a commissioner since 2008, and her term was not set to expire until the end of this year. Walter could slip into the job that Mary Schapiro left vacant in December without Senate confirmation. And she had worked at the agency in various capacities for about two decades.

“I don’t know of anyone else who could have made that transition as easily as Elisse,” said Arthur Levitt, a former SEC chairman and Walter’s former boss. “She’s been through so many of these transitions during her time there, and she knows the place inside out.”

Still, the situation is unusual. Agency observers figured the White House had more pressing nominations to attend to than the SEC slot. But the president acted swiftly. Walter was about a month into her new job when he nominated White, who still awaits a Senate confirmation hearing.

“She was a lame duck even before she got started,” said Barbara Roper of the Consumer Federation of America. “But I don’t get the impression that the other commissioners are looking past her, and treating her as a short-timer. . . . There’s a lot of impatience on a number of fronts, and people don’t want her to sit and wait for the next chairman to figure it out.”

That’s the way Walter sees it too.

She’s already filled two key positions, hiring a general counsel and chief accountant. And she has met with European regulators in Brussels to discuss cross-border financial issues.

In January, during her first public appearance as chairman, Walter laid the groundwork for the months ahead and vowed to take care of business on which the agency had fallen woefully behind.

At the top of the agenda is wrapping up the regulations mandated by the Dodd-Frank financial overhaul law, most of which have yet to be finalized. The SEC also must tackle rules tied to a one-year-old law that make it easier for private firms to raise money.

Walter declined to commit to timing, but she said ignoring these rules is not an option.

Technology is also a point of focus for the agency, Walter said, and she plans to discuss the topic at length on Tuesday at the American University Washington College of Law.

In recent years, the agency’s credibility has suffered from a series of high-profile glitches in the market, particularly the harrowing “flash crash” of May 2010, when the stock market plunged nearly 1,000 points, then whipsawed back up. The agency has purchased software that enables it for the first time to stream real-time data from the public exchanges into SEC headquarters, so it can track market activity and reconstruct events.

During her Tuesday speech, Walter will announce that she has asked the SEC staff to use that data to analyze how quickly trades are made and canceled so that the agency can better understand the high-speed trades that now dominate the market. She also wants the staff to explore how it can share its analyses with the public.

Whether Walter can tackle even a few of these issues during the limited time she has left at the agency is an open question, especially since the commission is evenly split between Republicans and Democrats, a formula for gridlock. But this year is basically her last shot.

When her term expires in December, Walter said she will leave the SEC.

Her original plan was to retire in 2010. But that was before she was tapped as a commissioner, her “dream job.” And before her term was extended to 2013. All of that was on the table when she spoke to the White House about succeeding Schapiro.

“At 63, I did not want another five years, and being chairman was never my ambition. You always see the chairman as being in the crosshairs,” Walter said. “But I must say that when the opportunity came, I was glad to do it. I’ve grown up here, and I’ve become more resilient, more willing to put myself forth.”