The brewery, which was founded in 1992 and employs 150 people, had revealed in April that it was exploring a sale or merger as a way of attracting new investment.
National law firm Freeths advised Breal Capital on the acquisition.
Freeths’ restructuring partner, John Jeffreys, said: “We are extremely pleased to have supported our client Breal Capital in this acquisition which represents an important addition to its existing portfolio.
“The future of this well-loved brewery has been secured with Breal’s support and we wish them every success.”
A spokesman for Black Sheep Brewery told the BBC: “This marks the next chapter in the history of Black Sheep as we look to grow the business in a sustainable way.
“Our team will continue to produce great beers from our landmark brewery in Masham.”
The brewery was founded by Paul Theakston to champion independent brewing following the sale of T&R Theakstons to a national brewer.
T&R Theakston has since been bought back into family control in 2003 via a deal led by Simon Theakston and his brothers.
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