MINNETONKA, Minn. ( TheStreet) -- UnitedHealth ( UNH) is nearing an agreement to buy closely held Executive Health Resources, a medical services firm, for about $1.5 billion, Bloomberg reports. UnitedHealth, the insurer, would added Executive Health to its Ingenix database management and consulting unit, Bloomberg reports, citing three people with knowledge of the talks. The deal for Executive Health, which is backed by Abry Partners LLC, could be an all-cash deal. An agreement could be days away and could still fall apart, the people said, Bloomberg reports. Executive Health provides hospitals with teams of outside physician advisers to improve regulatory compliance and efficiency, Bloomberg says. -- Written by Joseph Woelfel in New York. Get more stock ideas and investing advice on our sister site, Stockpickr.com.