The contract that saw the inauguration of Apple as a company has sold for just under $1.6 million - over ten times the pre-sale estimate.
The documents were signed on 1 April 1976 by the company's three co-founders Steve Jobs, Steve Wozniak and Ronald Wayne.
Wayne is credited with having the business expertise that the other two founders lacked: indeed, Steven Jobs later said to biographer Walter Isaacson: "Ron was an amazing guy. He started companies. I had never met anyone like that."
However, Wayne quit the company just days later, and the contract includes an amendment withdrawing his share. He sold the papers in 1994 to Wade Saadi, founder and chief executive of IT recruitment firm Pencom Systems.
The successful bidder was Eduardo Cisneros, chief executive of Miami-based Cisneros Corporation. He hasn't said what he plans to do with the documents, but tweeted: "Very happy to own a piece of American (World) history!"
Wayne quit the company in such short order because of fears that his assets could be seized if Apple proved unsuccessful, returning to work at Atari. His shares, at the time, amounted to ten percent of the company and netted him just $800, although he later received a further $1,500 payout.
At today's value, Wayne's shares would now be worth more than $36 billion. Nevertheless, he told the Daily Telegraph last year that he had no regrets.
"Would I like to be rich? Everybody would like to be rich, but I couldn't keep up the pace," he said. "I would have been wealthy, but I would have been the richest man in the cemetery."