Mark Sainsbury and Michael Benyan, the group’s owners, founded Zetter over 18 years ago.
Orca plans to maintain and grow the Townhouses brand, and are currently looking for more properties in the UK to acquire.
Speaking on the sale, Benyan said: “We are extremely proud of the culture of The Zetter Group, the unique hospitality brands we created and the impact they had on London’s vibrant hotel, restaurant and cocktail scene.
“The fact that Orca Holding are passionate about The Zetter brand and have such exciting plans for its future, is great news for all involved and we wish them every success.”
Pharaon said: “We see huge growth and development potential in The Zetter Group. This has been a difficult year for most hotels but the properties were previously achieving great success in their respective segments.