AT&T, the second largest U.S. wireless carrier, is on track to smash record smartphone sales in the fourth quarter as the company revealed on Wednesday that it has already sold six million smartphones in the first two months.

So far the record of this company’s smartphone sales is 6.1 million set in the third quarter of 2010. AT&T’s CFO John Stephens said at a Wednesday press conference that the company expected this quarter to be their strongest smartphone sales quarter. With about 100,000 smartphones sold every day, AT&T is very likely to set a new record this quarter given that the company has the usually demanding December sales yet to go.

Typically the fourth quarter sees increasing sales of new smartphones as the holiday season is a good time for many consumers to upgrade their handsets.

A big reason for the sales boost in the fourth quarter is the delay in the launch of Apple’s iPhone 4S this year, which set the stage for a pent-up demand during October and November. Earlier, AT&T claimed that it sold over one million iPhone 4S in just five days after the device was released in the market. Sterne, Agee & Leach Inc. on Wednesday also revised its speculation of the total iPhone sales from 26 million to 28 million.

AT&T's Stephens said the company saw more iPhone upgrades this quarter than the previous quarter as many customers were waiting for the new iPhone. Although this year more carriers began selling iPhone, many customers chose to stay with AT&T. Stephens said it shows AT&T's customers are loyal.

Stephens also said that customers stay with AT&T because they enjoy the experience on the company’s network and they will love the company more as , by the end of December, the company’s high-speed 4G LTE network will be available for all of its customers.

Last month the company’s merger plan for Deutsche Telekom’s T-Mobile USA hit the skids in Washington, facing an antitrust suit filed by the Department of Justice. However, Stephens revealed that AT&T is still making efforts to complete the purchase. But he did not divulge any details of how they are seeking the approval for this deal.