(RECAP: Rents are soaring and demand for apartments is historically high, but some developers and landlords are overestimating the strength of the U.S. apartment market — and paying for it in quarterly earnings. Others are warning that the second half of this year will be even tougher. Construction of new multifamily units has been robust over the past five years, far outpacing that of single-family homes, but most of the product is in pricey markets and pricier neighborhoods, not in areas where demand is highest. That is because the costs of land and construction rose.)