Failed Democratic presidential nominee Sen. John Kerry’s (D., Mass.) long history of ethically dubious investments could invite controversy as he takes on a new role as a "top surrogate" for President Obama’s reelection campaign.

Kerry’s net worth as listed on his 2011 financial disclosure form is at least $193 million and likely much higher, making him the wealthiest member of the Senate. He is also a prolific investor, maintaining an array of stocks and other holdings through a mix of family trusts, marital trusts, and commingled fund accounts with his wife, Big Ketchup baroness Teresa Heinz.

The five-term Senator has a well-documented history of investing in companies that would benefit from policies he supports, as well as making conveniently timed and highly profitable trades coinciding with the passage of major legislation and, in some cases, the dissemination of privileged information.

For years, Kerry has invested millions in a number of green energy companies that have benefitted from the president’s efforts to aggressively subsidize the industry with taxpayer dollars.

These companies include Exelon, which received a $646 million taxpayer-guaranteed loan in 2011 to build a solar facility in California and created only 20 permanent jobs, as well as Fisker Automotive, the fledgling electric car company that offshored its manufacturing operation to Finland after receiving a $529 million federal loan guarantee in 2010.

The loan guarantees, approved by the Department of Energy, were made possible by funding allocated in the 2009 stimulus bill, which Kerry supported. According to Kerry’s own office, the Senator "played a key role" in crafting the portions of the legislation designed to offer federal support for green energy projects.

Additionally, Kerry co-authored the controversial cap-and-trade legislation that would have effectively imposed a tax on carbon-dioxide emissions. Though the bill ultimately failed, the New York Times noted that Exelon and companies like it "would emerge as financial winners" if the legislation was enacted.

Kerry has hundreds of thousands of dollars invested in Kleiner Perkins Caufield & Byers (KPCB), a venture capital firm run by John Doerr, a prominent Obama donor who served on the president’s Economy Recovery Advisory Board.

The firm, where former vice president Al Gore is a partner, invests heavily in alternative energy companies such as Fisker Automotive and Amonix Inc., a Nevada-based solar panel manufacturer that laid off two-thirds of its workforce earlier this year despite receiving nearly $6 million in federal tax credits.

Amonix was one of 16 companies (out of 27 overall) listed in Doerr’s "green-tech" portfolio to receive some form of federal support under Obama.

Kerry purchased—through family trusts—between $30,000 and $100,000 worth of shares in a number of KPCB investment funds, including its "Green Growth Fund," and continued to purchase shares throughout 2010, according to the Senator’s financial disclosure forms.

Kerry is one of several lawmakers prominently featured in Throw Them All Out, Peter Schweizer’s landmark book on how elected politicians exploit their privileged positions to enhance their personal wealth.

The Massachusetts Senator’s most dubious trading activity coincided with two major political events—the financial crisis of late 2008 and the passage of President Obama’s controversial healthcare overhaul in March 2010.

Kerry was one of at least 10 Senators to trade financial stocks just days after a Sept. 16, 2008 meeting between Treasury Sec. Henry Paulson, Federal Reserve chairman Ben Bernanke, and leading members of Congress to discuss the increasingly dire state of the financial markets.

In mid-October 2008, as the Treasury was discussing which banks would be bailed out in the Trouble Asset Relief Program (TARP), Kerry bought up to $550,000 worth of Citigroup stock and up to $350,000 worth of Bank of America shares. Days later, the American public learned that Citigroup would receive $50 billion from the TARP fund and up to $277 billion in additional loan guarantees. Bank of America also received $50 billion from TARP.

During the contentious healthcare debate in 2009, Schweizer noted, Kerry loaded up on pharmaceutical stocks, purchasing close to $750,000 worth of shares in one company—Teva Pharmaceuticals—in the month of November alone.

Drug companies were viewed to be among the major beneficiaries of the Democratic healthcare legislation. Pharmaceuticals "kicked in $80 billion to help make the bill work, but stand to make 10 times that amount in revenues from added government and government-subsidized business," liberal columnist Howard Fineman wrote in Newsweek.

Teva stock was trading at about $50 a share when Kerry started buying, but jumped to $62 a share after the healthcare bill was passed, an increase of nearly 25 percent. After Obama signed the bill into law, Kerry sold his Teva shares, realizing tens of thousands in capital gains.

Kerry also bought shares of ResMed, a company that makes medical devices, which surged more than 70 percent after the healthcare bill’s passage. Throughout the healthcare negotiations, Kerry consistently opposed efforts to increase taxes on companies like ResMed.

He also purchased stock in Thermo Fisher Scientific, a firm providing products and services to hospitals, at $35 a share. After passage, they were trading at $50 a share, an increase of more than 40 percent.

As Kerry was buying shares of companies certain to benefit from healthcare reform, he was selling stock in healthcare insurance providers, which were deemed big losers under the new law.

That is hardly the extent of Kerry’s questionable dealings, however. He has millions of dollars invested in funds operated by some of his largest campaign donors, including Bain Capital, Beacon Capital Partners, and the Blackstone Group, investment firms that have collectively given more than $170,000 to Kerry’s campaigns since 2007.

The Washington Free Beacon reported in February that Kerry helped secure a $3.5 billion windfall for hospitals in Massachusetts that would net tens of millions in new federal support for Partners HealthCare, another prominent campaign donor.

Kerry’s controversial financial activity could complicate his recently announced role as a top surrogate for Obama’s reelection campaign. The president has repeatedly sought to blame wealthy investors such as Kerry for precipitating the financial crisis of 2008 and has expressed sympathy for the controversial "Occupy Wall Street" movement, which has become notorious for advocating and in many cases carrying out vandalism against large banks and investment firms.

Employing Kerry as a prominent campaign spokesman could also unwittingly highlight a popular criticism of the president—that his major policy initiatives have had little impact on the struggling economy but have succeeded in enriching a small number of wealthy supporters.