Jet Black iPhone 7. Image source: Apple.

Just because Apple (NASDAQ:AAPL) has decided not to brag about preorders or launch weekend sales anymore doesn't mean that other companies won't. While the broader market has been fairly weak this morning, Apple shares are standing out and enjoying gains of over 2%. Apple has a couple of its carrier partners to thank. T-Mobile (NASDAQ:TMUS) and Sprint (NYSE:S), the No. 3 and No. 4 domestic carriers, respectively, have taken the opportunity to tout some early figures for the iPhone 7 and 7 Plus.

Without giving too much detail, the Un-carrier has announced that iPhone 7 and 7 Plus preorders have shattered all prior iPhone preorder records, jumping nearly four times compared to the prior record. Friday's preorder extravaganza set a single-day sales record for any device at the company. It probably helps that T-Mobile has been running an aggressive promotion, offering a base iPhone 7 for free when customers trade in an iPhone 6 or newer. The other carriers have more or less matched this offer.

Sprint's release was comparably strong. The company says that iPhone 7 and 7 Plus preorders over the first three days jumped 375% compared to last year. Customer order rates are about four times higher than last time around. The time frame that Sprint is referring to covers three days, compared to the four-day period that T-Mobile is disclosing.

Two's company

While the two larger carriers are staying quiet for the most part, it's conceivable that they're enjoying similarly strong demand for Apple's forthcoming flagship device. Apple expects the iPhone 7 launch to be supply constrained, and shipping date estimates for new preorders on its website have already slipped. In some cases, new preorders won't ship until November.

Apple is in the midst of an ongoing push to shift the investing narrative away from iPhone unit sales, but iPhone still accounts for nearly two-thirds of total revenue, so it's going to take a lot more time before investors turn their attention to recurring revenue sources. Meanwhile, Apple has now put up the first year-over-year declines in the product's history, so the pressure is on for the iPhone 7 to deliver, especially since Apple is taking a risk by using the same overall industrial design for a third year.

Evan Niu, CFA owns shares of Apple. The Motley Fool owns shares of and recommends Apple. The Motley Fool has the following options: long January 2018 $90 calls on Apple and short January 2018 $95 calls on Apple. The Motley Fool recommends T-Mobile US. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.