These included additional information and reporting obligations and the requirement that countries operating such programmes ensure that they do not adversely affect the food security of other members. In some cases, the objective may be to maintain an emergency reserve to protect against domestic supply shocks, reflecting a reluctance to rely entirely on international markets to ensure adequate food availability. Such emergency reserves generally involve purchases at market prices, food security programmes operated along these lines are not constrained under WTO rules. In other cases, stockholding policies involve purchases at prices higher than prevailing market prices, and in this case WTO limitations on domestic support do apply. Public stocks may be held as part of a domestic price stabilisation policy, or to stimulate production and incomes.