Here are five of the most important things to know about Trump's business career.
1. He has a talent for real estate, but that hasn't always translated well to other industries
Trump has forged a successful real estate career over 45 years, profiting from flagship buildings like the Trump Tower on Fifth Avenue in Manhattan, the Trump Tower Chicago, and Mar-a-Lago, a private club in Palm Beach, Fla. His Trump Organisation owns a portfolio of buildings, hotels and gold courses around the world.
Yet his real estate business isn't exactly the dominant force he suggests. Despite a national reputation as a New York property mogul, Trump doesn't make it into top 10 lists of the city's real estate players.
While his dealings in hotels and golf courses around the world appear to be success - his companies are privately held, so details are scarce - forays into casinos, airlines, professional football and other industries have ended badly.
His casino business, which produced the four bankruptcies that political opponents often hammer him about, is probably his most infamous flop. Though Trump paints these Chapter 11 bankruptcies as if they were a good deal, saying they allowed him to get out of a failing Atlantic City business at a strategic time, the 1991 bankruptcy proceedings brought him close to losing much of his personal fortune. As Drew Harwell and Jacob Bogage wrote for The Washington Post, Trump had to put millions of dollars of his own money into struggling companies, sold his yacht and his airline, gave up substantial ownership stakes and decision-making roles, and even agreed to limits on his own personal spending.
Today, Trump describes these bankruptcies as if no one was hurt in the process, except high rollers and sharks. Trump has said that he has started hundreds of companies, but only used bankruptcy proceedings four times. And he claims that Atlantic City has been a losing proposition for most entrepreneurs. "Almost every hotel in Atlantic City has either been in bankruptcy or will be in bankruptcy," Trump said during the third Republican debate.
Michael D'Antonio, who wrote a recent biography of Trump, says that is an incomplete assessment.
"But there were many people who weren't wealthy who lost money on those bankruptcies," he said. "Anyone who invested in a bond fund or who bought individual securities that were linked to his casinos lost money."
According to the New York Times, Wall Street banks remain hesitant to deal with Trump, due to the previous bankruptcies and his litigious nature. According to Federal Election Commission disclosures, 15 companies associated with Trump owe more than $270 million to banks. Trump has responded to these critiques by saying that he doesn't use Wall Street because he doesn't need the money - he's rich enough to do his own financing.
Another long and strange story is Trump's involvement with professional football in the 1980s. In 1984, Trump bought the New Jersey Generals, a team in the nascent and briefly-lived United States Football League, which played its games in the spring, after the Super Bowl.
In New York Times writer Joe Nocera's account, Trump's aim was in large part to have the league acquired by the National Football League, in the same way that the American Football League merged with the NFL in 1966. Trump led a charge to move the league's games from the spring to the fall, when they would go head-to-head with the NFL. Instead of merging with the NFL, the USFL simply flopped.
"I think he's very good at real estate, I don't think he's very good at other things," says biographer D'Antonio. "He tried to run an airline and failed at that. He tried to run casinos and failed four times. That's not evidence of brilliance when it comes to operating a complex business."
Trump has acknowledged a tendency to get bored easily with business ventures. "The same assets that excite me in the chase, often, once they are acquired, leave me bored," Trump wrote in one of his books. "For me, you see, the important thing is the getting, not the having."
2. Trump is not a self-made man
One of Marco Rubio's top zingers in the debate last week was that if Trump hadn't gotten an inheritance of $200 million from his father, he'd be "selling watches" in the streets of Manhattan. Rubio got the figures about Trump's inheritance wrong - $200 million is actually what Trump's dad's fortune was estimated at in the 1970s, not Trump's inheritance - but there doesn't appear to much that Trump benefited from the wealth and connections of his father, a developer named Fred Trump.
One of the richest people in America in the 1970s, Fred Trump built his real estate empire by developing apartments for middle-class families in Brooklyn, Queens and Staten Island after World War II. After the younger Trump graduated from the University of Pennsylvania's Wharton School in 1968, he joined his dad's firm and, in 1971, took over the business. He built on his dad's success, deploying leveraged capital on risky ventures that paid off: the Grand Hyatt Hotel on East 42nd Street, the Trump Tower on Fifth Avenue, and Trump Plaza on 61st and Third Avenue.
What Trump benefited most from initially was his dad's credit-worthiness, says D'Antonio. "When he wanted to go into business on his own, his father's credit was available to him, and that was worth tens of millions of dollars."
Still, there are questions over how much wealth Trump created. In the debate last week, Trump claimed that he took a loan of $1 million from his father and he turned it into a fortune of $10 billion. But The Post's fact checkers say that neither claim is quite right.
The $1 million loan doesn't include any of the benefits Trump received from his family's connections and joining his father's real estate business after he graduated from college, and it doesn't count an estimated $40 million inheritance in 1974. And the $10 billion figure, which is what Trump claims as his current net worth, is disputed. Bloomberg News has estimated his net worth at only $2.9 billion, while Forbes put it at $4.1 billion. Since Trump's businesses aren't public, the true figure isn't clear.
As my colleague Max Ehrenfreund has argued, even if Trump has many billions of dollars, there's an open question over whether it reflects true business acumen.
Business Week estimated Trump's net worth at $100 million in 1978. If Trump had merely put that money in an index fund based on the Standard & Poor's 500 index - the kind many Americans use to save for retirement - he would be worth $6 billion today.
3. Everything Trump touches turns to "Trump"
Trump has a kind of Midas touch: Many of the businesses he comes in contact with end up with his last name on them, often in large, gilded capital letters. Of the 515 companies that Trump has a part in running, 268 bear his last name, according to a filing with the Federal Election Commission.
D'Antonio says the strategy of branding and franchising is unusual for a businessperson, and more reminiscent of a professional athlete. "Donald is brilliant about turning himself into a walking brand, and he seized that opportunity pretty early," he says.
Trump's penchant for deploying his name has been a successful marketing strategy, but it also appears to satisfy a deeper desire for fame and accomplishment.
In addition to the Trump hotels and casinos, there are Trump-branded steaks (developed for the Sharper Image catalogue, but still served in Trump hotel restaurants), a Trump board game, the now-defunct Trump magazine and Trump Airlines, and a line of shirts and ties called the Donald J. Trump Signature Collection. Trump has put his name on water, Israeli energy drinks, cologne Virginian wine, vodka, furniture - "almost anything that might be sold as high quality, high cost, and high-class," D'Antonio writes.
The Trump brand family also includes the strange saga of Trump University, which has been the subject of intense criticism by his political rivals. As The Post's Emma Brown wrote in September, Trump University was not a university at all, but a series of motivational workshops and real estate industry tips that were held in hotel ballrooms beginning in 2004.
Students paid several thousand dollars for a three-day course, and up to $35,000 for more extensive mentoring and workshop packages. Some were under the impression that they would be mentored by Trump himself, but in the end the closest they got was a cardboard cutout of Trump they could take a picture with.
Trump still faces lawsuits from the venture, including a $40 million suit from the New York attorney general for defrauding students and operating an unlicensed university.
Trump responded to comments about Trump University in Thursday's debate by calling the lawsuits "nonsense."
"It's something I could have settled many times. I could settle it right now for very little money, but I don't want to do it out of principle," he said. "The people that took the course all signed -- most -- many -- many signed report cards saying it was fantastic, it was wonderful, it was beautiful."
4. Trump's record includes some unsavory episodes
While Trump was never accused of doing anything illegal, he worked extensively with companies controlled by the mafia on properties in New York and Atlantic City, including Trump Tower and Trump Plaza.
Some would say that was the only way to develop property in New York in the 1970s and 1980s - the mob controlled many parts of the city's construction industry, including concrete, labor unions and trash disposal. Still, the extent of Trump's involvement is certainly unique. "No serious presidential candidate has ever had Trump's depth of documented business relationships with mob-controlled entities," The Post's Robert O'Hara Jr. wrote.
Trump has said that he did not know these companies' mafia connections, adding that they were "unbelievably good contractors in terms of doing the work."
As Republican opponents have pointed out, Trump's businesses also appear to have hired undocumented and guest workers - which now prove awkward for a presidential candidate running on an anti-immigration platform.
Construction workers at Trump's new D.C. hotel told The Washington Post that some workers were undocumented, while the New York Times reported that Trump's Mar-a-Lago Club in Palm Beach rejected hundreds of applications from Americans only to bring in hundreds of Romanian guest workers.
As Rubio recounted in the debate Thursday night, Trump also faced a long-running lawsuit over the use of undocumented workers at the Trump Tower on Fifth Avenue in Manhattan. The building was allegedly built by undocumented Polish workers who were paid $5 an hour or less, when they were paid at all. The case dragged on for decades. The judged ruled that Trump knew that Polish workers were working off the books, were paid illegally and sub-standardly. Trump appealed, and the case was ultimately settled in 1999.
There were other strange incidents. The lawyer who represented the Polish workers claimed that someone named "John Baron" had called to threaten him with a lawsuit if he kept causing trouble, as Michael Daly writes for The Daily Beast. Trump denied making the call, but he used the pseudonym John Baron throughout his career. He suggested the name "John Barron" for the main character in a never-produced TV show called "The Tower" that was loosely based on Trump's life, and he and Melania later named their son Barron.
When Rubio brought up the Polish workers in Thursday's debate, Trump responded by saying he had hired tens of thousands of people in his lifetime, and that, at the time, "the laws were totally different. That was a whole different world."
5. Trump's genius is building a brand, even a mythology
In the 1980s, Donald Trump was short on cash but eager to get Holiday Inn involved in a new casino project in Atlantic City. The construction wasn't far along, but the Holiday Inn executives were coming to town, and Trump wanted to impress them. So he ordered a construction crew to dig up piles of dirt and drive them around on the site as energetically as possible. When the Holiday Inn executives came to town, they were impressed and agreed to invest, Trump says in "The Art of the Deal."
Trump's may or may not be the businessman he makes himself out to be, but there's little doubt his greatest talent is constructing a larger-than-life public figure. D'Antonio says he thinks Trump has worked to create a strong brand mostly because his ego "needed the attention." However, Trump also figured out how to make the attention profitable as well.
Trump's personal brand got a huge boost from "The Apprentice," the reality TV show in which Trump came off as a straight-talking truth-teller - "a decider who insisted on standards in a country that had somehow slipped into handing out trophies just for showing up," as The Post's Mark Fisher writes. In a recent book, Trump wrote that he didn't do the show for money, but rather because of the "brand presence."
Through his career, Trump has had a knack for converting his outrageousness into profit. Now, says D'Antonio, Trump is trying to convert it into votes.
