Moral trade is the process where individuals or groups with different moral views agree to take actions or exchange resources in order to bring about outcomes which are better from the perspective of everyone involved.
Take the following example: Greg's moral view assigns more weight to the current plight of nonhuman animals than it does to extreme poverty, and Paul's moral view assigns more weight to poverty than to non-human animals. Greg doesn't currently make donations to anti-poverty charities, but believes it would be better if he did, and Paul isn't vegetarian, but believes it would be better if he was. Greg has a strong moral preference for Paul to be a vegetarian, and Paul has a strong moral preference for Greg to donate more to anti-poverty charities. They propose a trade: Paul will become a vegetarian, if Greg agrees to give up some basic luxuries and give 1% of his income to anti-poverty charity. This outcome is better from the view of both Paul and Greg's moral theories.
Moral trade allows new opportunities for coordinated action that are morally Pareto optimal[1] —that is, situations where the coordinated action is better by the view of all parties, than the alternative.