An anti-speculation clause is a clause in a purchase contract that prevents a property buyer from quickly reselling the property for profit. The clause requires the buyer to occupy or use the property himself for a certain period of time. Sometimes it requires prior approval for sale or states that a portion of the profit must be surrendered to the previous owner. This clause is often used by municipalities to prevent price driving and speculative trading. Violation can lead to hefty fines, and the clause is often included as a chain clause, meaning that any new owner must pass on this obligation.