Trump is the presumptive Republican presidential nominee. Image source: Donald J. Trump for President.

While Donald Trump likes to tout his business prowess as a key reason people should vote for him, a number of his ventures have not been entirely successful.

Of course the candidate himself tends to deny that, sometimes in colorful ways, like bringing "Trump steaks"  to a March campaign event, though the beef turned out to not actually be Trump Steaks). The business mogul has also been quick to defend other less-than-successful ventures, like the casinos that carry his name, and his self-titled university.

Trump fought back aggressively when Mitt Romney -- a successful businessman and a former Republican nominee for president -- gave a speech that included the Yoda-like statement about Trump: "a business genius he is not." That prompted the real estate titan/reality show host to label Romney a "choke artist" and a "failed candidate," while noting that the former governor of Massachusetts "begged" for Trump's endorsement in 2012.

"I could have said, 'Mitt drop to your knees,' and he would have dropped to his knees," Trump said, NBC News reported.

But, while it's fair to say that Trump may not consider any of these businesses failures, it's reasonable to say that not everything Trump touches turns to gold (though it will be painted or packaged in the color). This is a man who has been unquestionably successful -- someone who turned family millions into billions -- but some of his companies and products have been less successful than others.

Trump Steaks: Despite Trump's steak display at his campaign event earlier this year and his reported statement that they were "Trump steaks," his self-titled meat brand is no longer in business, according to Bloomberg, which reported that the meat shown off in March was actually from Bush Brothers Provision Co., a West Palm Beach, Florida, company. Trump Steaks, when they existed, were actually sold through the Sharper Image catalogue and stores, which are also defunct (though the brand has been revived under different owners).

Trump casinos: Trump's involvement in the casinos bearing his name has been complicated. He sold the company which owns the properties, Trump Entertainment Resorts, in a 2009 bankruptcy reorganization plan, Politico reported. By the time it filed for Chapter 11 protection again in 2014, Trump was only a figurehead licensing his name to the company which now consists of only the Trump Taj Mahal Hotel and Casino in Atlantic City.

Trump University: Never actually a university or even an accredited school, Trump University launched in 2005, selling classes purporting to teach the businessman's real estate and entrepreneurship strategies. Price were steep -- from $1,500 to $35,000 per class -- and the school is currently the subject of lawsuit filed by New York Attorney General Eric Schneiderman. The lawsuit calls the school a "scam" and claims it defrauded about 600 students out of thousands of dollars. There are also two federal cases open against the school.

Trump has denied defrauding anyone and claimed that the school had a 98%  approval rating, according to NBC News, which also noted that he has filed a complaint alleging that the AG's office was looking for a campaign contribution. The candidate has also said California lawsuits have no merit, but regardless of the pending legal action, the school no longer exists.

Trump Airlines: In 1988 Trump bought the former Eastern Airlines Shuttle, which ran hourly flights between Boston, New York, and Washington. He paid $365 million for the fleet of 17 airplanes, Time.com reported, and even more as he spruced them up, giving the former no-frills service a higher-end sheen (including gold-colored bathroom fixtures).

"A lack of increased interest from customers (who favored the airline for its convenience not its fancy new look) combined with high pre–Gulf War fuel prices meant the shuttle never turned a profit," according to the news magazine's website. "The high debt forced Trump to default on his loans, and ownership of the company was turned over to creditors."

Trump Shuttle flew its last flight in 1992.

Trump Vodka: "I'm not a drinker, and I'm proud not to be a drinker," said Trump at the 2006 launch of his vodka line, which may have not been the way to get the public excited about the brand.

It appears the public did not want a vodka from a man famous for not drinking. Even though at the time of its release Trump said "I fully expect the most called for cocktail in America to be the T&T or the Trump and Tonic," according to Rolling Stonepeople simply were not buying. The trademark was abandoned in 2008 and the liquor was no longer sold as of 2011, reported the magazine.

GoTrump.com: Though this URL now directs people to Trump's campaign website, it was once used for a travel website the mogul launched with his usual flair in 2006. The site, which was powered by Travelocity, offered Trump Picks" and "Trump Deals," and it even shared what was claimed to be Trump's "first-ever email address" ([email protected]) which he would be using to "offer travel tips and advice," Money reported.

At the time of it's launch, financial analyst Henry Harteveldt of Forrester Research called GoTrump.com a "vanity site" that won't make much money, The Washington Post reported. That proved prophetic as it was shuttered after about a year.

Trump Magazine: It took chutzpah to launch a magazine in 2007 given what print publishers were already experiencing at the time due to the Internet, but Trump clearly thought his brand would enough to get past that trend. Described in a press release at its launch as "[reflecting] the passions of its affluent readership by tapping into a rich cultural tapestry," according to Time, it folded about 18 months later in 2009.