When the race is opened for entries the British Horseracing Authority sets down the maximum weight a horse can carry.
The BHA has set down the maximum weight for a race at 9st 10lbs.
All of the horses in the race are available to be ‘claimed’ (i.e. bought) at a price of £12,000 irrespective of their finishing position if they run off the maximum weight.
The trainer can then select the weight his horse carries and for each 1lb he takes off his horse’s back the claiming price comes down by £1,000.
So, if a trainer really wants to get rid of a horse he could take off 10lbs and his horse would be able to be claimed for just £2,000.
Alternatively, if one of the horses in this race runs off a weight of 9st 10lbs (i.e. the maximum weight allowed in this instance), to claim him would cost £12,000. This would suggest the trainer of that horses is probably therefore not looking to have his horse claimed.
Most trainers run their horses in claimers not to be claimed, but for the prize money, as they are often running off smaller and more equal weights than they would be in a handicap.