While most potential 2016 GOP White House contenders now appear to be focusing more on building the groundwork for a campaign, former Florida Republican Gov. Jeb Bush seems just as busy developing his business interests.

It's a break in style from recent candidates who have distanced themselves from the sometimes politically risky business of making money before running.

When some possible GOP contenders, including New Jersey Gov. Chris Christie and Kentucky Sen. Rand Paul, spoke at the Conservative Political Action Conference in Washington this year, for example, Bush declined to appear because of undisclosed business commitments.

However, he has traveled the country this year raising money for Republicans and continues to work on education issues at his foundation.

Bush has headlined more than two dozen private fundraisers, including events to help the governors of Iowa, South Carolina and Nevada, three of the first four states to hold presidential primaries. This past week he attended fundraisers for Illinois gubernatorial hopeful Bruce Rauner and Senate Minority Leader Mitch McConnell, R-Ky.

"He's quietly active. He just doesn't go out and bang the drum," said Mel Sembler, a Florida real estate developer and top Republican fundraiser. "He's doing all the right things, and I think he's going to be a serious contender."

A Republican establishment favorite, Bush is chairman of a Florida-based private equity and business advisory group, and is a managing partner of at least eight other separate companies that dabble in ventures ranging from privatized emergency response to real estate to driverless cars, according to state and federal records.

He trails only Christie in an averaging of early 2016 GOP White House polls by the nonpartisan website RealClearPolitics.

In the past three years, regulatory filings show that Bush and his partners at the private equity firm, Britton Hill Holdings, have branched out into nearly a dozen different investment entities and raised at least $66.4 million from domestic and foreign investors. That includes several million this past April from a group that included a privately owned Chinese conglomerate, a deal first reported by Bloomberg.

Bush says he will make a decision about 2016 by year's end. Should he run, this son and brother of the past two Republican presidents will like other candidates face pressure to disclose years of personal tax returns and details about his private business activity, as well as to unwind his ownership in the business network he began building after leaving office in 2007.

For now, in much the same way he is quietly working to support GOP candidates in the November elections, Bush's business deals are made out of the spotlight. There is no suggestion any are improper. Because they are private enterprises and disclosure laws require only basic information, public documents offer few details about their exact nature.

They are, however, reminiscent of the GOP's last presidential nominee, Mitt Romney, who struggled at times to explain the often complicated ways he made a living. Romney, as well as Bush's father and brother, wound down personal business affairs years before running for president.

"It is a legitimate issue to think about," said Ron Kaufman, a former Romney adviser who is close to the Bush family. "In a perfect world, would he be better served if (the presidential race) was four years away? Sure. But it's not."

Bush declined a request for an interview.

Those close to him say that after his two terms as governor, he has worked aggressively to improve his personal finances, a common practice for politicians after public service.

Bush "is not currently a candidate for office. He's a businessman," said his spokeswoman, Kristy Campbell. "If he makes a decision to run for president, he would certainly review his work engagements at that time."

Other Bush confidants caution against reading too much into his business dealings. They believe he is well positioned to wait longer than other candidates to make a call on a campaign because of his political connections and deep fundraising network.

"You don't put your life on hold or call a time out. You move on until you make a decision," said Al Cardenas, a Bush friend and adviser. "He enjoys what he's doing. Investors trust him. So why would you put a stop to that?"

Operatives in both parties said the calculus isn't that simple.

In 2012, Romney was attacked by other Republicans as a "vulture capitalist," which helped create the portrait of job-destroying buyout chief who enjoyed a lower tax rate than most people in the United States.

"It is a target-rich environment for opposition research teams to pour through and begin to build a narrative that you're out of touch," said South Carolina-based Republican operative Hogan Gidley. "It sounds like he's doing everything right, everything above board. But the political reality exists that it still might hurt him."

Cardenas rejects the comparison to Romney, whose Bain Capital held a majority stake in dozens of companies and directly oversaw management decisions. Bush, unlike Romney, will not be defined by his "fairly modest" investments, Cardenas said, adding that comparing the two is "the difference between running a gas station and running Texaco."

Friends and former aides say Bush's behavior is consistent with the way he handled his business affairs while contemplating runs for governor in 1994 and 1998.

"Before he was a candidate, he was a businessman, and he conducted his business sort of not thinking about his next (political) move. He just did it," said Phil Handy, a Florida businessman who was chairman of Bush's gubernatorial campaigns. "I think it reflects his ambivalence about running for office, but I don't think it's at all unusual."

Still, at this point in their political careers, Romney and the previous Bush presidents had all but exited the business world.

Bush's father, former President George H. W. Bush, turned his financial affairs over to a blind trust once he became vice president. Jeb Bush's brother, former President George W. Bush, sold stocks with connections to Mideast oil companies roughly a decade before running. He later put the majority of his assets into treasury notes and a blind trust.

The Associated Press contributed to this report.