The investors, Filmyard, includes construction magnate Ron Tutor and investment firm Colony Capital.
Disney has been negotiating with potential buyers for months to sell the division, which has made films such as Pulp Fiction and Shakespeare in Love.
Earlier this week, Disney bought the social gaming developer Playdom.
"Although we are very proud of Miramax's many accomplishments, our current strategy for Walt Disney Studios is to focus on the development of great motion pictures under the Disney, Pixar and Marvel brands," Disney's chief executive Robert Iger said.
Disney wants to concentrate on these family-orientated divisions, which produce popular films such as Toy Story, that also come with highly profitable merchandising opportunities.
"Disney has been very smart with its film strategy," media analyst Theresa Wise told BBC World Business Report.
"One of the big issues with movies is very few films break even... so they need other revenues. Disney has the fantastic ability to sell family films and all the merchandise that goes with it.
Disney has owned Miramax since 1993 when it bought the firm from Hollywood heavyweights Harvey and Bob Weinstein.
The Weinstein brothers, who recently attempted to buy it back from Disney, named the film company after their parents Miriam and Max.

The body of James Chadwick, 37, was found at an address in Holland Street last Wednesday.
At Aberdeen Sheriff Court, Ryan Gibb and Cameron Laurie, both 30, were charged with murder and attempting to defeat the ends of justice.
They made no plea and were remanded in custody. They are due to appear in court again next week.

The victim was found with serious injuries at a house in Unsworth Way in Oldham, Greater Manchester, at about 19:50 GMT on Thursday.
He was taken to hospital and died a short time later. Details of his injuries have not yet been revealed.
The house was cordoned off while police carried out an investigation. A 58-year-old woman has been taken into custody for questioning.

Officers described the incident near Blairhill Station, in Coatbridge, North Lanarkshire, on Sunday night as "stupid and dangerous".
The shopping trolley was hurled through overhead power lines which could have electrocuted the person.
A train hit the trolley, but there was no serious damage to the vehicle or any injuries on board.
British Transport Police have appealed for anyone with information to contact them.
PC Mark Harrington said: "We believe the trolley was thrown onto the tracks before the train struck it.
"It's incredible that whoever threw it was not electrocuted, as the trolley has gone between the overhead wires.
"This was a stupid and dangerous thing to do and could have had very serious consequences, not only for the person throwing the trolley but also for the driver and all the passengers of the train that collided with it.
"This happened in a residential area so it is likely that someone will have seen or heard people by the tracks around the time of the incident.
"I would like to speak to anyone who has any information that could help with this investigation."

The Mystery Plays were first performed in York in the 14th Century and traditionally involve just one professional actor.
The plays will return to the Minster in June 2016. More than 28,000 people attended its last productions in 2000.
The 800-year-old gothic cathedral will host a month-long staging of the plays.
The Very Reverend Vivienne Faull, Dean of York Minster, said: "After a gap of 16 years it is a great pleasure and enormously exciting to confirm the staging of this second, landmark production of the Mystery Plays at York Minster."
In 2014 the plays were staged on wagons travelling around the city's streets.
The plays are described as telling the story of the world from the beginning of all things to the end of all things.
The performances traditionally take place on the feast day of Corpus Christi, which can fall in either May or June.
Nicola Corp, who has worked on projects for the BBC and Capital Radio, has been appointed to produce the event.
Entertainment giant Walt Disney has announced the sale of its Miramax film division for about $660m to a group of private equity investors.
[NEXT_CONCEPT]
Two men have appeared in court charged with the murder of a man in Aberdeen.
[NEXT_CONCEPT]
A woman has been arrested on suspicion of murdering a 56-year-old man.
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A person who threw a trolley onto train tracks is lucky to be alive, transport police have said.
[NEXT_CONCEPT]
A centuries-old series of plays performed by amateur actors is set to return to York Minster for the first time in 16 years.