If insufficient coverage is purchased to rebuild the home, the claim's payout may be subject to a co-insurance penalty. In this scenario, the insured will be subject to an out of pocket fee as a penalty. Insurers use vendors to estimate the costs, including CoreLogic subsidiary Marshall Swift-Boeckh, Verisk PropertyProfile, and E2Value, but leave the responsibility ultimately up to the consumer. In 2013, a survey found that about 60% of homes are undervalued by an estimated 17 percent. In some cases, estimates can be too low because of "demand surge" after a catastrophe. As a safeguard against a wrong estimate, some insurers offer "extended replacement cost" add-ons ("endorsements") which provide extra coverage if the limit is reached.