Ah, but you’re evidently forgetting that earnings are inflating too. By and large the corporations have great pricing power now, and the real wages they’re paying (their biggest operating costs typically) are falling quite precipitously. (Tight labor markets? Get back to us when real wages start rising even slightly.) Corporate balance sheets are great, too. I wouldn’t bank on that PE simply because the E looks like it’s doing really well. I don’t like to make such forecasts, but if pressed things look broadly quite good among the S&P 500 companies.
If E keeps rising but P just kind of stays parked at low 4,000ish (let’s suppose), you never get in at 3,800 even while the PE falls. Has this happened before? Absolutely it has. The S&P 500 can go through long periods moving basically sideways. So if you want to make a PE argument then why don’t you have a PE-based trigger?
As far as 19.4, we haven’t seen anything even slightly lower since (briefly) late 2018/early 2019. And before that we haven’t seen anything lower since mid to late 2014, on the bull run up from the Global Financial Crisis. (And there was nothing like the GFC since the Great Depression.) The S&P 500 index ended 2018 at about 2,500. You’d be thrilled right now (I hope) if you got in at 2,500 less than 3 1/2 years ago.
Anyway, good luck to you, but I’m with Shiny. I wouldn’t bother trying to time this market and would just dollar cost average in at a reasonably expeditious pace. That’ll also work great in the scenario when the S&P 500 crosses 3,800 and continues to 3,300 over the next 3 months (let’s suppose). A 6 month DCA starting now would do very well in that scenario too.
And why the S&P 500 anyway? Just go with the MSCI or FTSE global index, e.g. VWRA or ISAC.