Part of Gingrich's empire, a kind of Gingrich, Inc., includes several for-profit businesses. Gingrich Communications oversees his paid speaking engagements and Fox News contract. Gingrich Group provides consulting services. Gingrich Productions makes feel-good documentaries with themes grounded in religion and American tradition.
This week Gingrich also released his 24th book, with many of his upcoming campaign stops doubling as marketing events for his book and movies, raising more questions about the true intentions of the campaign.
"If he's being driven by book sales, and movie openings and things like that, that doesn't fit into a traditional campaign," said Reed.
Also raising questions from independent watchdog groups is the operation of a charity Gingrich founded, called Renewing American Leadership.
Its website contained ads for Gingrich's books -- taken down after ABC News asked about them -- and posted his positions on political hot-button issues.
"It's not clear that it is a charity," said Ellen Miller, executive director of the non-partisan good government group The Sunlight Foundation. "We have an organization that looks like he's mixing public purpose and his own private political purpose."
The charity's fundraising letters, on Gingrich's letterhead, attack President Obama and also promote Gingrich's book.
In fact, records show the charity bought Gingrich's books to give to those who send in donations.
There was no discount in the price, according to the charity's new director, Pastor Jim Garlow.
"My concern was, 'Is there any way we can get these a lot cheaper?' and we couldn't and we didn't," said Garlow.
A recent audit discovered that the charity paid one of Gingrich's for-profit companies more than $200,000, which the charity says was used to pay his then-press secretary Rick Tyler, who was also the director of the charity -- until March -- and made the decision to buy the Gingrich books with charity funds.
Garlow said he didn't think Gingrich's charity and political career had become too intertwined, and accused ABC News of misreading Gingrich's intent.
Said Garlow, "What's so intriguing about you, in the media, you can't believe people have pure motives. That's so hard for you. So difficult for you. You assume everyone's got evil motives."
Gingrich refused repeated requests to be interviewed about his empire, and had little to say when ABC News caught up with him Tuesday morning on his way to a speech.
"I'm not concerned about that," said Gingrich. "The American people are not concerned about that. Cover the speech."