Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

What investments are positively related to the housing market decline?
A possibility could be real estate brokerage firms such as Realogy or Prudential. Although a brokerage commission is linked to the sale prices it is more directly impacted by sales volume. If volume is maintained or goes up a real estate brokerage firm can actually profit rather handsomely in an up market or a down market.  If sales volume does go up another option would be other service markets for real estate such as real estate information and marketing websites and sources i.e. http://www.trulia.com. Furthermore one can go and make a broad generalization such as since real estate no longer requires the same quantity of construction material other industries sensitive to the price of those commodities should technically have a lower cost of doing business. But be careful in the US much of the wealth an average american has is in their home. In this case this means that the economy as a whole takes a dive due to consumer uncertainty. In which case safe havens could benefit, may be things like Proctor & Gamble, gold, or treasuries. Side Note: You can always short builders or someone who loses if the housing market declines, this will make your investment higher as a result of the security going lower.