Comcast's ( CMCSA) gleaming image shatters as competition drags the cable giant into a price scuffle.

The Philadelphia cable shop cut its cash flow target for the year as phone companies and satellite players show they can pick off Comcast customers more easily than expected.

Suddenly the sales growth in new services like broadband and phone has slowed. The number of new services sold or revenue generating units fell to 1.4 million, down from 1.5 million last quarter.

Instead of seeing pressure from one large rival, the competition was more "product specific," says one industry investor. In video, Comcast took a beating from the satellite broadcasters EchoStar ( DISH) and DirecTV ( DTV). And telcos like AT&T ( T) and Verizon ( VZ) pushed hard on phone and fast Internet services, says the money manager who owns no Comcast.

"The concern as an investor is that the impact from competition will only grow," says the money manager.

Attempting to keep sentiments positive on the stock, Comcast said it would boost its share buyback plan by $7 billion, though there was no specific timeframe announced.

For the third quarter, Comcast made $560 million, or 18 cents a share, down from the year-ago $1.22 billion, or 38 cents a share. Revenue rose 21% from a year ago to $7.78 billion.

Analysts were looking for an 18-cent profit on sales of $7.76 billion.

The company added 489,000 new digital cable subscribers in the latest quarter but lost 65,000 basic cable users. The company added 450,000 high-speed Internet customers and 662,000 phone users.

To some degree, the economy is a concern, broadband as a market might be getting mature, and competition is getting stiffer, says the investment manager.

"People thought this was a high-quality double-digit growth company and now they find out its growth will be less than expected," says the money manager. But he thinks today's move in the stock "might be an over-reaction."

Comcast shares fell $2.39, or 10%, to $21.46 in midday trading Thursday.