> Retail traders that started "investing" in the last two years have been trained to believe that stock splits means a bunch of money will pile in because the price looks cheaper

I have heard this exact thing debated since the late 80's, so I'm not sure what the last two years has to do with it. The fact is, whether there's a real effect there or not depends less on the precise math of the situation and a whole lot of behavioral and psychological factors. Splits goosing the stock price is a real thing that happens. It may be entirely self-perpetuating crowd-mind BS but it does still happen.

Retail has easier access to options & day trading now than in the 80's.

Stock split results in much cheaper options, which many retail day traders seem to prefer.

I might argue that a stock split to a cheaper price would increase your volatility due to the above. Though TSLA's current price might disagree with me as I think it's one of the most traded & is by no means cheap for options trading.

It also allows options trading by retail investors (options are traded in 100 share tranches, which for GOOG or AMZN right now means your minimum option trade is on an underlying value of ~$250K, meaning a 5-10% swing is... significant.). Splits make options trading more accessible to retail investors by dropping the minimum risk 10-20x which also might cause a natural demand increase.

> Obviously there has never been a correlation there and even less so now with the wide availability of fractional shares.

Splits have historically caused price bumps, so I think this isn't true.

Recent research in behavioral econ actually supports that a lower price on the ticker leads to more retail investor buy-in. I forget who, but it was a Yale professor who wrote a paper on this in the 2010s -- she gave a talk at D.E. Shaw back when I was an undergrad visiting for a summer program.

I guess all I want to say is that it's more nuanced than 'obvious' and is probably an active debate right now for economists, but I wouldn't know more exact details.

I heard it might also mean that it can then be added to the dow index which might trigger some automatic buying?

I'd expect that to be negligible because the size of funds Google is already part of (QQQ, VTI, SPY, etc. etc.) are orders of magnitude larger than ETFs that track the Dow (DIA is the only one that comes to mind).

The Dow itself is a bit of gimmick in that its value is the sum of all the prices of the stocks in the index. Meaning if Google joins at $120 but kicks out a stock that was $300 then the Dow would go down 180 points.

No, it wouldn't. The Dow is weighted for exactly this reason: https://en.wikipedia.org/wiki/Dow_Jones_Industrial_Average#C...

maybe you should get off the high horse and do some research as to the factors that could lead the stock price goes up during splits - not going to list it here due to your condescending tone