What happened

Automotive giant General Motors (GM 4.37%) is having a terrific Tuesday, as its stock had risen a solid 5% at 11:40 a.m. ET.

So why is GM stock humming today? Curiously enough, it's because of the GM Hummer.

GM electric Hummer pickup.

Image source: General Motors.

So what

As CNBC reports, General Motors has so far racked up more than 65,000 reservations from customers interested in buying its new electric Hummer pickups and SUVs. In and of itself, that's an encouraging sign of consumer willingness to pay up for vehicles that will probably be priced well north of $100,000 (in initial versions at least). But the news is actually even better than it sounds.   

CNBC quotes GMC global vice president Duncan Aldred confirming that reservations are running ahead of expectations and saying that "momentum [is] building." What's more, "Production's actually slightly ahead of plan," says the VP, "and we're putting things in place now to actually expedite that as well, so we can deliver these reservations quicker than we originally thought."

Now what

"Quicker," of course, is a relative term. Although the company has begun sales of the Hummer EV pickup already, volume is infinitesimal at present -- a single truck sold in December, for example. (A more current count should arrive with GM's Q1 2022 earnings report on Friday).

Real sales volume isn't expected to begin for this EV before 2023 for the SUV version of the Hummer or 2024 for the pickup. As Aldred said, "A reservation now probably means delivering in '24."

So don't expect to see Hummer sales contribute in any meaningful way to GM's results later this week. When it comes to Hummer and earnings, it's going to be all about the guidance.