What happened

Shares of Ford Motor Company (F) stock fell hard in afternoon trading Thursday, down 4.3% as of 1:20 p.m. ET.

You can blame Barclays Capital for that.

A person waves down a police car next to a car wreck in a ditch.

Image source: Getty Images.

So what

The British banker downgraded Ford shares to equal weight this morning, you see, and slashed its price target on Ford by 26%, to just $17 per share, as StreetInsider.com reported.

Ford looks "vulnerable to the ongoing chip shortage," warns Barclays, having secured supplies of only about one-third of the semiconductor chips it needs to build its targeted number of automobiles this year and those at higher prices than they cost a couple of years ago. Ford isn't the only company at risk. Shifting to a "negative" stance on the entire U.S. auto sector and lowering its price target on General Motors (GM -1.73%) stock as well, Barclays warned that "investors are still underestimating ongoing risks to the sector -- and in particular to suppliers -- from inflation, ongoing production pressures, oil prices and consumer weakness (at least in Europe)."

Now what

Inflation raises the cost of buying new cars and trucks, depressing sales in an era already starting to show signs of consumer weakness. It also raises the cost of goods sold, thus squeezing Ford's profit margins on both ends. At the same time, higher oil prices may depress sales of Ford's biggest profit-earners -- big pickup trucks and SUVs -- and shift market share more toward sales of "econoboxes" (which Ford doesn't sell anymore) and electric cars (which it's only getting started selling).

Long story short, there are a lot of reasons to be pessimistic about Ford stock today and precious few reasons to be optimistic.