The "Spread Loss" operation eliminates the loss on your horse completely by backing it to cover its liability. Needless to say, all other horses will get a huge red figure, especially if your horse is an obvious favourite.
The "Distribute the loss" operation equalises the loss on all selections by greening them down (or redding them up), in other words, by hedging.
Which one to pick depends on the level of risk you are prepared to take.
