The first is with Australian auctioneers Leonard Joel, established in Melbourne in 1919 and still the auctioneer with the largest number of specialist departments in the country.
The firms will assist each other with the marketing and sale of select auctions in categories that will benefit from exposure to their respective markets.
For John Albrecht of Leonard Joel this means direct access to global clients via London, giving Australian consignors a better chance to sell art and antiques of European origin in a more competitive environment. There is likely to be a special emphasis on numismatic items thanks to the British-based operation now being part of Stanley Gibbons.
Dreweatts & Bloomsbury, by turn, can extend their marketing of select auctions to the Australasian region.
Stephan Ludwig, CEO of Dreweatts & Bloomsbury Auctions, said: "The advancement of technology continues to shrink the collecting world and our global client base will benefit from enhanced access to local knowledge. This alliance will provide Australasian stamp and coin collectors with direct access to our world-class numismatic and philatelic expertise."
Mr Albrecht said: "This will give Leonard Joel sellers better access to UK/European buyers, Leonard Joel buyers better and more secure access to UK/European auctions and, equally, give Dreweatts & Bloomsbury sellers better access to Australasian buyers and Dreweatts & Bloomsbury buyers better and more secure access to Australasian auctions. I think it is an elegant and interesting win-win."
Meanwhile, Dreweatts & Bloomsbury are also teaming up with classic car specialists H&H Auctions of Warrington, Cheshire, who were founded by Simon Hope 21 years ago.
"The new pairing will offer collectors access to a comprehensive range of dedicated specialists, whose expertise spans the world of rare art, watches, silver, books, maps, motor vehicles and automobilia," said Mr Ludwig. "The classic car has become an important passion for many of our clients."
The two partnerships follow a long list of acquisitions and take-overs involving Dreweatts' parent company, the Fine Art Auction group, which culminated in its acquisition by Stanley Gibbons and the recent take-over of Mayfair and New York dealership Mallett.
Mr Ludwig advised ATG to expect further initiatives to develop the group before the year is out.