Shinzo last year provided Tom Magnier with one of his greatest thrills in a lifetime in racing when he won the $5 million Group 1 Golden Slipper.

It was the first time the Coolmore navy blue had been carried to victory in the world's richest two-year-old event, the most significant race for breeders in Australia, and was the first win in the race by a male product of one of Australia's all-time great stallions, Snitzel.

It all but assured Shinzo will retire the highest-profile member of his freshmen stallion crop when he does go off to stud.

Magnier can therefore barely believe Coolmore is back with an even stronger hand in this year's Golden Slipper.

Coolmore now has the controlling stake in raging favourite Storm Boy, a horse it bred and sold before buying back in a multi-million-dollar deal after his win in the Magic Millions 2YO Classic, along with second favourite Switzerland.

Like Shinzo, Switzerland is a son of Snitzel who is raced by the group of significant industry heavy-hitters that form Coolmore's 'colts fund', which was formed to unearth stallion prospects.

"Obviously, last year we had Shinzo in that partnership as well – we bred Shinzo for the colts fund – and that was obviously a huge kick for them," Magnier said.

"But to go back again this year and have bought Switzerland off John Messara for $1.5 million, it's a massive endorsement for the team that we have at the farm.

"They really are good horsemen and good judges, right through to the people who pick them as yearlings."

Switzerland was a $1.5 million buy out of the Arrowfield Stud draft at last year's Inglis Easter Yearling Sale.

That sum is small compared to what Coolmore paid for Storm Boy, or the bonuses it will pay to Storm Boy's original owners if that son of Justify wins the races Gai Waterhouse and Adrian Bott have set him for this campaign, but it is part of a big investment strategy.

Switzerland was not even the colts fund's biggest buy at Easter last year, having gone to $1.6m for the colt by Snitzel out of Ultimate Fever, who is now known as Imperial Force.

They also paid $1.2m for a colt by I Am Invincible and $1m for another son of Snitzel, while at last year's January Magic Millions Sale on the Gold Coast they bought the $2.7m sale-topping I Am Invincible colt.

Seeing the likes of Shinzo and Switzerland achieve what they have done so early in the careers is what drives the Coolmore strategy.

"Just to have these horses in the Slipper, I'm delighted for the partners that are in the horse because they put so much faith in us," Magnier said.

"It's great to be able to be here again this year."

Part of the appeal of Switzerland was the American speed his dam Ms Bad Behavior brings to Australia.

A daughter of Blame, Ms Bad Behavior is out of a Stormy Atlantic mare and was a winner at Group 3 level over 1609m in the US.

Russian Revolution, Little Brose and Wild Ruler are some Australian Group 1-winning sprinters from recent seasons who are out of American mares.

Coolmore's determination to buy back into Storm Boy stems from him being by its burgeoning superstar sire Justify, a son of Scat Daddy who won the US Triple Crown at three, which underlines its faith in American progeny.

"The American blood does very well here, even when you look at the whole Scat Daddy line down through Justify, it's all working well down here," Magnier said.

"If you look back to Danehill, he was American blood, so it has worked here before and it's been very successful and we've used a fair bit of it as well."

Danehill is the equal most successful sire in Golden Slipper history, having produced five winners, while his son Redoute's Choice has provided two winners, including Miss Finland, who was out of the US mare Forest Pearl.