The 2010 Melbourne Cup winner Americain is to stand at the famed US stud Calumet Farm following a deal in which 50 per cent of the horse was sold to an American owner.

The US-bred, French-trained and Australian-owned galloper raced for the past three seasons for Australian owners Gerry and Val Ryan and Kevin and Colleen Bamford who have retained a 50 per cent share of the horse.

Melbourne-based bloodstock agent Robert Roulston, who helped stitch up the deal, said Americain would leave Australian in mid-December.

After a brief quarantine period in California he will take up residence at the farm located in the heart of Kentucky's famous bluegrass country.

Americain will begin serving mares in February.

One of the most widely-travelled horses in the thoroughbred world, Americain began his life in the United States and started his racing career in France where he won at his first start.

He then returned to the US where he raced four times without success.

After returning to France he regained form and was purchased by his Australian owners in 2010 and made the first of three trips to Melbourne.

Americain's new part-owner, who prefers anonymity, also owned the horse's sire Dynaformer who died earlier this year.

"He was keen to buy a well-performed son of Dynaformer which is what attracted him to Americain," Roulston said.

Calumet Farm sold for around $40 million last May in a complex deal that involved his new part-owner.

Americain will return to Australia for the southern hemisphere breeding season with a stud deal yet to be finalised.