On Tuesday, Ford Motor Company (F -0.40%) jubilantly announced that its U.S. vehicle deliveries surged more than 30% year over year last month.

There's just one problem: June 2021 was a horrible month for Ford. At that time, its sales plummeted by 27% as the global chip shortage was wreaking havoc on its production and sales. Moreover, on a year-to-date basis in 2022, deliveries are down 8% even though Ford has faced easy year-over-year comparisons.

Ford appears to be losing share in key market segments. Unfortunately, the automaker is spinning the numbers to make them appear better than they are rather than explaining to investors what is going on. That's a concerning development for Ford shareholders like me.

A subpar month

While Ford's June 2022 sales release mentioned "ongoing industry semiconductor chip and supply constraints," it mainly focused on year-over-year sales gains and market share increases for various models last month. This presents a misleading picture to investors.

For example, dealers delivered 57,673 F-Series trucks in the U.S. last month, up 26% year over year. But that was still down from 65,188 deliveries in June 2020 (in the early days of the COVID-19 pandemic, no less) and 79,204 deliveries in June 2018.

In total, Ford's 152,252 domestic deliveries in June represented a 34% drop compared to June 2018. (Ford didn't report monthly sales in 2019 or 2020.) Its results aren't much better on a year-to-date basis. Ford dealers delivered 915,820 vehicles in the U.S. in the first half of 2022: down 26% from the first half of 2019 and down 28% from the first half of 2018.

A Ford Bronco Sport driving through shallow water.

Image source: Ford Motor Company.

To be sure, sales are down across the whole industry, mainly because of supply constraints. But Ford has suffered significantly worse declines than most of its rivals.

Losing share in lucrative market segments

In its recent sales release, Ford also stated, "F-Series has been expanding its truck leadership through the first half of the year, outselling its second-place competitor by about 40,000 trucks."

This was also a big exaggeration. First, Ford's F-Series trucks only outsold General Motors' (GM 0.18%) Chevy Silverado by 35,206 units in the first half of the year. Second, GM also builds a second high-volume full-size truck model: the GMC Sierra. The combined domestic deliveries of the Silverado and Sierra have outpaced the F-Series by 28% (83,732 units) year to date.

Indeed, GM's year-to-date U.S. full-size truck deliveries are up significantly compared to 2019 and down just 2% from 2018. F-Series deliveries have plummeted by roughly a third over the same period.

Similarly, while Ford seemed to be gaining traction in the lucrative full-size SUV market a few years ago, deliveries of the Ford Expedition and Lincoln Navigator have fallen by 45% year to date compared to the same stretch of 2019. GM's U.S. full-size SUV deliveries slipped by just 7% relative to 2019's first half.

What's really going on?

In short, it doesn't take a deep dive into Ford's U.S. sales results to see that it has gotten off to a weak start in 2022. Regardless of whether you compare the Blue Oval to its competitors or to its own results from a few years ago, the company is underperforming.

The bigger problem for investors is that the company hasn't provided a clear explanation for why it is losing market share. Perhaps supply chain bottlenecks remain the key issue. If so, that wouldn't be too concerning, as long as Ford expects to be able to ramp up production again soon.

On the other hand, if Ford has voluntarily slowed production of some models because demand for them is faltering, that would be far more worrisome. Ford should stop pretending that its 2022 sales numbers have been good (or even halfway decent) and instead focus on explaining why they have lagged -- and when the tide is likely to turn.