AT&T and Verizon are expected to post double-digit IPTV subscriber growth in their respective third quarter releases, according to analyst firm Strategy Analytics.

The firm estimates that Verizon’s FiOS TV customer base will grow 12% in the quarter, exceeding 2.8 million total subscribers. Meanwhile, AT&T is expected to add over 250,000 new U-verse subs, implying a 17% sequential growth rate. A recent report published by Strategy Analytics shows US IPTV growing to 15.5 million subscribers by 2013. This growth, however, will hinge upon the ability of Telcos to articulate the value of IPTV, according to Strategy Analytics.

“Telcos need to go beyond trying to simply replicate the cable experience,” said Ben Piper, analyst and Director of the Strategy Analytics Multiplay Market Dynamics service. “Content does matter, but so do features. Operators able to optimize relevant feature sets for customers will ultimately succeed.”

The total US Telco TV market, estimated at 4.6 million subscribers in Q3’09, will near 5.3 million subscribers by year-end, according to Strategy Analytics.