Before making an aggressive offer, some homework is in order, real-estate professionals say. And buyers will need to effectively explain why the price of a home should be lower. Even though housing is in a slump in many parts of the U.S., low-ball offers won’t work in markets that remain healthy. And there’s always an inherent danger in going too low. A low offer could insult the seller to the point that they’ll refuse to counter, Realtors say. And the seller could easily make the assumption that the buyer isn’t committed to making a deal. Certain sellers are going to be more willing than others to negotiate a low offer — and there are several giveaways that might indicate more leeway on price. If the sellers have already purchased another home and that sale has closed, they’re likely to be more willing to make a deal.