Americain has been given top weight of 58kg for the Emirates Melbourne Cup at Flemington on November 1.
The Alain de Royer-Dupre-trained six-year-old shouldered 54.5kg when victorious in the race 12 months ago.
The top-three-weighted horses in this year's Melbourne Cup are all internationals, with Brian Meehan's Dangerous Midge on 57.5kg and Irish St Leger winner Jukebox Jury, trained by Mark Johnston, on 57kg.
Johnston also has Fox Hunt (53kg) entered.
Godolphin's Cavalryman has been allocated 55kg, with emerging stablemate Lost In The Moment given 53kg.
Red Cadeaux, third in the Irish St Leger, has 53.5kg, while David Lanigan's Meeznah, impressive in the Park Hill Stakes at Doncaster on Thursday, is the highest-weighted mare on 53kg.
Dermot Weld's entrants, Galileo's Choice and Sense Of Purpose, have received 52.5kg and 51.5kg respectively.
However, the former has yet to pass the first ballot, while Sense Of Purpose has been ruled out for the rest of the season.
Luca Cumani's Bauer (52kg), the Melbourne Cup runner-up in 2008, has also yet to pass the first ballot. Of the other internationals nominated for the Melbourne Cup only, the Brian Ellison-trained pair of Saptapadi and Ebor hero Moyenne Corniche both have 52kg and are not yet guaranteed a start.
Several runners have progressed in the weights for the Melbourne Cup as a result of victories since the release of the Caulfield Cup weights, including the Michael Stoute-trained Modun.
The four-year-old, who did not accept for the Caulfield Cup last week after being an original entry, has risen from 51kg to 53kg following victory in the September Stakes at Kempton.
Jukebox Jury is a possible for the Melbourne Cup after his rousing dead-heat with Duncan in the Irish St Leger. Connections of the Alan Spence-owned grey will study the weights before deciding whether to go for the Flemington showpiece.
Jukebox Jury was already certain to go globe-trotting, with races such as the Canadian International, Japan Cup and Hong Kong Vase likely targets, but now a trip to Oz could be on the cards.
"He's come out of the race really well," said Johnston's wife and assistant, Deirdre. "I checked him over when he got back on Sunday night and he's in great order. The Canadian International is a possibility as his next race and we are discussing the Melbourne Cup as well.
"He's so versatile and goes on any ground. He's a real laid-back traveller, so it's the right kind of thing for him. We're just going to wait and see and decide in a few days' time."
The two Ellison horses leave for Australia on September 22 and the North Yorkshire trainer plans to give them a prep race in the hope they can earn a penalty to ensure places in the showpiece.
"They fly out on the 22nd of this month and can run anytime from October 8," Ellison said.
"Basically we will be trying to find a race out there to try to get a small penalty to get them in the Melbourne Cup."