Fascinating piece in today's Financial Times by Rachel Pagones, bloodstock editor of the Racing Post, on John Magnier and the Coolmore stud. When they started off with Green God they charged 1,500 guineas for him to cover a mare. Now at his Ashford satellite in Kentucky, stallions with Storm Cat for sire or grand-sire can ask for $500,000. Coolmore earn 70.5% of the Irish bloodstock industry's income. Bloodstock is now throroughly globalised: Green God would cover 40 mares a season, while one of Coolmore's stallions in 2004 will cover 200 and then head for the southern hemisphere to do the same again in their season.
Magnier and his associates had two new ideas: syndication of stallion ownership, unusual when they started off in 1971 and buying yearlings, then a twentieth of the price of stallions. This allowed them to buy more and offset the cost of duds against those they got right: they reckoned they needed to get it right every four or five times.
I think full text is only available on the FT site to subscriber., but the article is worth reading and is:
Pagones, Rachel
How Magnier became king of the turf
Financial Times January 29 2004: 18

