What happened 

Shares of Ford Motor Company (F 0.47%) were moving higher on Friday on growing signs of high demand for and consumer excitement about the company's upcoming F-150 Lightning electric pickup truck. 

As of 1 p.m. EDT, Ford's shares were up about 6.2% from Thursday's closing price.

So what

You probably know that Ford on Wednesday took the wraps off of the F-150 Lightning, the much-anticipated, battery-electric version of its huge-selling F-150 pickup truck. Aside from a few disgruntled Tesla (TSLA 1.85%) fans, the reception for the truck has been strongly positive thanks to its long list of features, competitive range (up to 300 miles), and surprisingly low starting price (just under $40,000 before government incentives).

How will that translate to sales? Ford CEO Jim Farley gave us a good early indication via Twitter on Friday morning.

As it did with the electric Mustang Mach-E earlier this year, Ford took a page from Tesla's playbook and opened an online reservation system when it revealed the F-150 Lightning on Wednesday night. A $100 refundable deposit secures a customer's place in line to order the F-150 Lightning.

A silver F-150 Lightning Limited parked at a campsite with its frunk open and four young campers nearby.

The F-150 Lightning's "Mega Power Frunk" -- a large front trunk fitted with electrical outlets -- could turn out to be a key selling point for the truck. Image source: Ford Motor Company.

On the one hand, it's just $100, and it's refundable. On the other, 44,500 reservations are a strong indicator of high interest in the electric truck, and that's why Ford's stock was surging on Friday. 

Now what

There are two important things that auto investors should know about the number that Farley tweeted on Friday morning. 

First, according to sources at Ford, those reservations are all from retail customers, an important distinction given that Ford put a lot of weight on the needs of its commercial and government fleet customers when designing the Lightning. (Sources at Ford say that a separate reservation system for fleet customers will open very soon.) 

Second, Ford has said that it will limit first-year production of the Lightning as it ramps up suppliers (including battery suppliers) and its own production line. (It is doing something similar with the Mach-E, which will be limited to 50,000 in its first year.) 

While Ford hasn't said what the limit on the Lightning's first year of production will be, veteran auto analyst Rod Lache of Wolfe Research said in a note on Thursday that based on conversations with suppliers, he thinks it'll be around 80,000. 

If so, and if fleet demand is as high as I think it will be, the 2022 F-150 Lightning could be sold out very soon. Stay tuned.