T-Mobile is making big subscriber gains in the fourth quarter, CFO Braxton Carter said, and it hopes to leverage the new iPhone X to increase its momentum.

But don’t hold your breath waiting for any two-for-one deals on Apple’s ultra-high-end phone.

“So far in the fourth quarter our porting rations are up significantly,” Carter told attendees at an investor conference in Barcelona, Spain, Thursday. “We ended the third quarter at a porting ratio of 1.53; we’re now 1.73 on porting ratios to date this quarter. And our porting ratios are up against every carrier, and fairly significantly. That’s pretty good movement just being roughly halfway through the fourth quarter versus what we saw in the third quarter. So the thesis is playing out.”

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Meanwhile, demand for the iPhone 8 has been weighed down by anticipation of the iPhone X, Carter said. Apple’s $1,000 device launched two weeks ago, providing T-Mobile—and its rivals—a big chance to poach customers when they upgrade to the most iconic phone on the market.

“We have been extremely happy with what we have seen with the iPhone X: great demand, great uptake, more supply than we anticipated, although going into the holiday season we do think we’ll be overall supply-constrained and roll over into the first quarter,” he continued. “But this is a unique opportunity. The price that consumers are paying … makes a perfect opportunity to look at other options and other carriers. And we are uniquely positioned to (take advantage), being the last to the iPhone and (having) the smallest embedded base, to take advantage of that and create more switching.”

And while the holiday season typically sees a slew of aggressive marketing campaigns as carriers look to add subscribers at the end of the year, the market has become relatively placid in recent months as operators hone their focus on high-value customers rather than overall market share. Churn is likely to edge up during the quarter, of course, but even the release of the iPhone X hasn’t prompted operators to offer bargain-basement deals.

And it doesn’t sound like T-Mobile will be going overboard with iPhone X promotions anytime soon.

“Certainly there will be periods of pulsing promotions like you always have in the fourth quarter, but overall rationality (of the) pricing of the iPhone 10 we’ve been really pleased about from a health standpoint in the U.S. wireless industry,” he said.

Whether that rationality survives the holiday season, of course, has yet to be seen.