WASHINGTON - Former Florida Gov. Jeb Bush, moving closer to a possible presidential run, has resigned all of his corporate and nonprofit board memberships, including with his own education foundation, his office said late Wednesday night.

He also resigned as a paid adviser to a for-profit education company that sells online courses to public university students in exchange for a share of their tuition payments.

Bush's New Year's Eve disclosure, coming in an aide's e-mail to the Washington Post, culminated a string of moves he has made in recent days to shed business interests that have enriched him since leaving office in 2007. The aide said the resignations had been made "effective today."

The aide said Bush was reviewing other businesses in which he is principal partner or owner, such as Jeb Bush & Associates, a consulting firm, and Britton Hill Partnership, a business advisory group that in 2013 set up private-equity funds investing in energy and aviation.

Aides said Bush wants to devote his time to exploring a return to politics rather than pursuing his business commitments. But separating himself from those interests now could also be a strategic attempt to prepare for the added scrutiny of a hotly contested campaign for the Republican nomination.

Bush's financial stake in Academic Partnerships, the online education firm, has been relatively small for a millionaire - a $60,000-a-year fee and ownership of a small amount of stock, said Randy Best, the company's founder and chief executive. Even so, Bush's affiliation with the firm - which has contracts with schools in a half-dozen states and several foreign countries and has annual sales of $100 million - could complicate his effort to promote his record as an education reformer.

The company receives up to 70 percent of the tuition some students pay to public universities, and some faculty members say it siphons money from the schools while asserting too much control over academic decisions.

Best, a Texas entrepreneur and major political donor, said his firm has increased professors' access to online students and helped schools attract additional revenue, while Bush aides say the former governor does not have business interests related to K-12 education, which has been his policy focus.

Transitioning for a run

Bush's decision to extricate himself from his private-sector work is "part and parcel of a process he is going through as he transitions to focus on a potential run for president," said his spokeswoman, Kristy Campbell. "This is a natural next step that will allow him to focus his time on gauging interest for a potential run."

The effort underscores the lengths to which Bush - who has become the favorite prospective candidate of many major GOP donors and has been at or near the top of polls testing the possible Republican presidential field - appears willing to go to avoid pitfalls that hurt the party in 2012. That year, GOP nominee Mitt Romney, founder of a private-equity fund, struggled to explain his business background.

Business credentials

Bush, 61, lamented Romney's handling of the criticism in an interview last month with Miami's WPLG-TV. Bush said the 2012 nominee allowed himself to be pulled "off message" and should have told voters: "I'm a problem-solver. My life has been about building things up."

Of his own business record, Bush said: "I'm not ashamed. Taking risk and creating jobs is something we ought to have more of."

Bush's business portfolio is far smaller than that of Romney, whose Bain Capital became one of the country's most successful private-equity firms. Yet it is complicated and could present political problems because he has been affiliated with a broad range of industries and businesses.

Barclays relationship

Bush announced last month that he was ending his consulting relationship with Barclays, the British investment-banking conglomerate. The New York Times reported in May that the firm paid Bush more than $1 million a year.

The bank, like other major Wall Street players, had been under scrutiny in recent years for alleged interest rate manipulations and for allegedly providing special benefits to big traders.

Recent Securities and Exchange Commission filings revealed that Bush was leaving the boards of two publicly traded firms: Rayonier, which invests in forest lands, and Tenet Healthcare, which backed President Obama's health-insurance initiative and profited from its passage.