Comcast Corp. sold bonds to finance its $39 billion acquisition of Sky Plc in one of the biggest corporate debt sales ever in the United States.

The Philadelphia-based cable giant sold $27 billion of unsecured bonds in 12 parts. The longest portion of the offering, a 40-year security, yields 1.75 percentage points above Treasuries, less than an initially discussed range of between 1.95 percentage points and 2 percentage points, according to a person with knowledge of the matter, who asked not to be identified as the details are private.

Comcast was able to cut the cost on its sale as investors put in orders for about $88 billion of the debt. A deal of that size was likely to draw strong demand, said David Knutson, head of credit research for the Americas at Schroder Investment Management.