I'd get back in ASAP.
I play an online game where you open crystals to get certain prizes of varying rarity. It's shocking the strategies people come up with, despite the devs being very clear that the probabilities are constant from crystal to crystal. Some people open them 1 at a time, some open 10 at a time, some open 1 until they get something good then open 10. Some open at certain times of day, or when someone else gets something good. It's all nonsense and confirmation bias, you should see the confidence people get when their strategy "works". They'll never change it again.
This forum is full of posts talking about how the top is in, the market has peaked, the bubble is soon to burst, etc. They come around every few months. Unfortunately most of them get lost in the mix, but if you search hard enough you can find them. This one was started in April of last year, we're currently up approximately 13% from the day it was posted. You can find them going all the way back to the start of the forum if you care to look. Most of them have very convincing theories about how we're overdue for a recession (been saying that since about 2012), the P/E ratio is inflated compared to historical averages (again, since probably 2012), America is dying due to foreign competition, etc etc.
https://forum.mrmoneymustache.com/investor-alley/top-is-in/Here's one from 2013, just went back through pages and randomly found it:
https://forum.mrmoneymustache.com/investor-alley/doom-and-gloom/Another one:
https://forum.mrmoneymustache.com/investor-alley/stock-market-expensive-now-alternatives/While the Shiller PE isn't near historical highs your statement is a little misleading/misinformed as there really are only three periods in the history where the Shiller PE was higher than now - right before the great depression and before the dot com crash and just slightly above where we are prior to the financial crisis.
So there may be room to run and push the markets but history is not on the side of good returns from this point.
We're up 51% since this post was made. A year after this post was made the market was up 15%. 2 months after this post was made the market was up 4.5%. The S&P 500 has never been lower than it was on Oct 28, 2013, since Oct 28, 2013 (at least, based on the resolution in my yahoo chart). Anyone who waited starting then lost money, no matter how perfect they timed a future drop.
I could post dozens of these threads, maybe hundreds, since this forum was started. Occasionally some of them will be right, but the problem is you don't know that until the time is past. Most of them are wrong. Most don't have actionable intel, just general negative feelings that you can't really act on in a productive way. Knowing that the market will probably crash in the next 1-5 years, or might just stagnate or have numerous small corrections, doesn't really help you. The most reliable information we have is the market usually goes up. Because of that long term trend, it's always better to get in as soon as you can, provided you don't need the money soon.
"Get in ASAP, with everything you can afford, for the long term" is a great rule of thumb, but I'd argue that the most import, typically last, and typically hardest thing to be learned about any rule of thumb is when it's not the best option.
A few things to keep in mind: people rightfully talk about the cost of opportunity but given that I'm only talking about sitting on the sidelines for a few days at most (assuming things don't start going up or really tanking) this is a largely mute point, it's not that hard to get lucky once if you have a few things going in your favor and I'd argue that I do (trade war, interest rates...), I'm only planning on doing this once so neither regression to the mean nor cost of opprotunity considerations are relevant, I'm not trying to pick a top AND a bottom (I got out for unrelated reasons) only the next bit of direction, the fact that the market's behaviors don't repeat with sufficient regularity for people to use them to consistently beat the market doesn't mean that zero insights can be gleaned.
I'm not convinced that this is a good idea, I'm just not convinced that it's an innately bad idea just because it's different from what I do the other 99% of the time since this is a different circumstance from the other 99% of the time (at least for me).
If you actually have some sort of insight that gives you the ability to time the market this time, why would you assume you can't do it any other time? Either you can do it or you can't.
Which is more likely:
You have a newfound ability to time the market one time that just so happens to exactly coincide with when your work plan was cashed out.
You see a big chunk of money and are getting a bit greedy/fearful because now it's cash and you have to make a decision. You're for some reason treating it differently than two weeks ago when it was already invested, and presumably you weren't talking about pulling it out to cash (the same decision in reverse) to prevent losses from a drop.