The Twitter account, which has an audience of more than 600,000 followers, has been the subject of an internal inquiry at Goldman to find the rogue employee. The tweets, often laced with insider references to deals in the news, appeal to Wall Street bankers and outsiders who mock the industry. Late last month, the writer sold a book about Wall Street culture based on the tweets for a six-figure sum.

There is a good reason Goldman Sachs has been unable to uncover its Twitter-happy employee: he doesn't work at the firm. And he never did.

The author is a 34-year-old former bond executive who lives in Texas. His name is John Lefevre.

He had tried to remain anonymous, scrubbing the internet of mentions of his name and pictures of himself on all but a handful of sites. Some people had already speculated that @GSElevator was not hanging around the halls of Goldman.

The ability of people like Mr Lefevre to create anonymous Twitter accounts underscores concerns about the veracity of what is published and the identity of authors. It also raises questions about whether publishers are blurring the line between real life and the made-up kind.

Upon being contacted late last week after several weeks of reporting uncovered his identity, he confirmed his alter ego. "Frankly, I'm surprised it has taken this long," he said by phone. "I knew this day would come."

Mr Lefevre, who worked for Citigroup for seven years, said the Twitter account started as "a joke to entertain myself."

He quickly interrupted the inevitable line of questioning about how he had never worked at Goldman and appeared to be an impostor. "To pre-empt what you're about to say, legally speaking," he said, "I was never explicitly an employee of the firm."

Mr Lefevre was offered a job as head of debt syndicate in Asia at Goldman's Hong Kong office in August 2010, but the offer was later revoked, according to people at the firm who spoke on the condition of anonymity. Mr Lefevre said his previous employer contended that he was bound by a noncompete agreement and "things turned nasty with my old boss and he threatened a lawsuit against me and Goldman."

By Mr Lefevre's own account of his experience with Goldman: "My contract was never rescinded. We cordially agreed to part ways to avoid a public mess. I don't know how much I can talk about it. It wasn't acrimonious."

When pressed about whether he had implicitly misrepresented himself as a Goldman employee, he said he deliberately never said in any of his tweets that he worked for the firm. "This was never about me as a person," he said. "It wasn't about a firm. The stories aren't Goldman Sachs in particular. It was about the culture in general."

A Goldman spokesman, after being told that @GSElevator had been unmasked, said in a statement, "We are pleased to report that the official ban on talking in elevators will be lifted effective immediately."

The fact that Mr Lefevre was not a Goldman employee did not appear to dissuade his publisher, Touchstone, an imprint of Simon & Schuster, which said it had not been misled.

"He's been pretty straight with us the entire time, so this is not a surprise," said the book's editor, Matthew Benjamin, who bought the book without ever meeting Mr Lefevre. "That you're writing about him speaks to the interest he's generated. We always expected his identity to be revealed at some point."

Mr Lefevre's agent, Byrd Leavell, said: "What matters is that every story in the book is true. John's material... is hilarious. The book isn't going to live or die on whether he worked at Goldman Sachs for two months or not."

Mr Lefevre, who started at Citigroup in New York in 2001 after graduating from Babson College before moving with the firm to London and then Hong Kong, said that he was inspired to start the Twitter account in the fall of 2011. "I was sitting around with a friend at a bar," he said.

At the time, an account called @CondeElevator had sprung up, supposedly chronicling the goings-on in the elevator of the media company Condé Nast. "I thought, 'This is ridiculous that people are infatuated with Condé Nast. If they only saw the elitist, sexist and out-of-touch things bankers say.' People had no idea what it is really like."

He said he chose to name his account after Goldman Sachs because "it was commercial." In an email, Mr Lefevre added, Goldman "has more love/hate Main Street appeal." At the time, the Occupy Wall Street movement was in full swing. He said he was also struck by some of the lines, comical to him, he heard from people at Goldman when he first received a job offer. "Even socialising with them — going to bars and having guys buy girls drinks and then throw out a line like, 'Don't worry ladies, these drinks are on Goldman Sachs.' "

#1: I start every cell conversation with 'my phone's about to die' so they don't waste my time.

Mr Lefevre insisted that many of the exchanges he published on Twitter were true: "I've been collecting these stories for years."

He said his intent was neither to mock nor glamorise Wall Street. "I do not have an agenda to paint the people or this culture one way or the other," he said, adding that he was "always a cynical banker" when he worked on Wall Street but "I loved it. We did a lot of crazy stuff. It's not like I had a great epiphany along the way."

Still, he said that working on Wall Street was an eye-opener. "I went into investment banking and I saw a group of people that aren't as impressive as I thought they were — or as impressive as they thought they were. They defined themselves as human beings by their jobs."

His Twitter feed has become red meat for industry critics, something Mr Lefevre said was initially unintentional but later something he tried to stoke. "A lot of times I pander, I'll be honest with you. I pander for retweets," he said.

He said his Twitter account had evolved over the last few years: "Early on, I tweeted more about specific people or deals, inside jokes/commentary, and even a few ad hominem attacks. That gave me a certain validation and credibility. But over time, the tweets have been increasingly styled to have a bit more commercial appeal.

"I don't consider it selling out or pandering to a lower common denominator; I think of it more as adapting to what the widest possible audience of people responds favourably to. "

#1: I start every cell conversation with 'my phone's about to die' so they don't waste my time.

Mr Lefevre, who refused to disclose his location in Texas, started worrying several months ago that his identity would be revealed. He received some emails from friends who had guessed it was him. He also noticed that some Goldman Sachs employees had viewed hisLinkedIn profile page; he later removed it.

Now that he has been outed, he said, "it's something that can be embraced. And I certainly don't have anything to hide."