What happened

Shares of air taxi start-up stock Archer Aviation (ACHR 1.00%) soared 6% through 10:50 a.m. ET on Friday, and it's no great secret why:

"Cathie Wood loves Archer Aviation."

So what

You all remember that famous scene from the movie Wall Street, right? Where Charlie Sheen's character starts a bull run on the fictional Anacott Steel by phoning in a tip that someone is buying up the shares?

Well, something similar seems to be happening today as investors learn that famed growth investor Cathie Wood and her ARK Innovation ETF (ARKK 1.05%) have been snapping up shares of Archer Aviation. According to ARK's real-time tally of stock purchases, Wood bought 2.69 million shares of Archer on Wednesday and 646,849 shares on Tuesday after acquiring 340,891 shares last Friday.

That's nearly 3.7 million shares acquired over just the past week -- about 1.45% of all Archer shares currently outstanding. What's more, the sizes of the buy orders Wood has been placing have been growing in size.

Now what

In fact, to really put these purchases in context, the last time Wood was spotted buying Archer shares was in June, when she acquired just 35,000 shares of the air taxi stock, and previous purchases were even smaller.

But if Wood was just dipping her toes in the water back then, well, this week, it's more like she's just shouting "cannonball" and leaping into the pool.

Now, admittedly, there's still the question of whether Wood is right to be buying Archer. After all, this is still a $1.5 billion company losing nearly $484 million a year while recording annual revenues of...zero. Cathie Wood or no Cathie Wood, Archer Aviation still looks like the very definition of a speculative investment to me.

That being said, it's well established at this point that where Cathie Wood leads, growth investors will often follow. And today, it's really looking like it's going to be an "everybody into the pool with Cathie" kind of day.