Existing-home sales fell back for the second straight month in May, as only the Northeast region saw an uptick in activity, according to the National Association of Realtors.

Total existing-home sales, which are completed transactions that include single-family homes, townhomes, condominiums and co-ops, decreased 0.4 percent to a seasonally adjusted annual rate of 5.43 million in May from downwardly revised 5.45 million in April. With last month's decline, sales are now 3.0 percent below a year ago and have fallen year-over-year for three straight months.