What happened

Shares of General Motors (GM -0.04%) were moving higher Tuesday on news that the company is making progress in rebuilding its U.S. inventories. A highly anticipated product reveal scheduled for Wednesday also added to investors' enthusiasm. 

As of 11:45 a.m. ET, GM's shares were up about 6.2% from Monday's closing price.

So what

GM, like most other global automakers, was forced to curtail production in 2021 amid supply chain challenges fueled by the COVID-19 pandemic. The company reported its fourth-quarter U.S. sales on Tuesday morning, and while they were down sharply from the year-ago period (as expected), there was some good news behind the headline numbers: GM's inventories are improving.

Specifically, GM said it had just under 200,000 vehicles at or in transit to its U.S. dealers as of the end of the quarter, up from just 129,000 at the end of October. That increase suggests that GM's supply chain issues are improving, which is a good sign -- as is having more vehicles on dealer lots, for reasons that should be obvious to auto investors.

That's a big part of why the stock is up today, but it's not the only reason.

A 2022 Cadillac Escalade, a large truck-based luxury SUV.

Sales of most GM products fell year over year, a result of supply chain disruptions that curtailed the company's manufacturing output. A profitable exception: Sales of the big Cadillac Escalade SUV were up 65% in 2021. Image source: General Motors.

Now what

The other part of the story: GM will reveal its much-anticipated electric Chevrolet Silverado pickup truck tomorrow. 

Investors and analysts rightly expect the battery-powered Silverado, which will be built on GM's second-generation Ultium EV architecture, to be a very big deal. Rival Ford Motor Company (F 0.08%) has seen extraordinary demand for its own electric pickup, the F-150 Lightning revealed last year. In fact, Ford said this morning that it has again boosted its production capacity for the Lightning, which will begin shipping in the second quarter. 

If you own GM stock (and I do), I encourage you to watch tomorrow's events closely.