Markets for some toxic assets froze in 2007, and the problem grew significantly worse in the second half of 2008. Several factors contributed to the freezing of toxic-asset markets. The value of the assets were very sensitive to economic conditions, and increased uncertainty in these conditions made it difficult to estimate the value of the assets. Banks and other, major financial-institutions were unwilling to sell the assets at significantly reduced prices, since lower prices would force them to significantly reduce their stated assets, making them appear insolvent.