When I read Buffett pumping money into Citi, I did my research. Sold put option on C back then and purchased at $46 a piece,  carried them for dividend for awhile until $63 and sold them all to save some cash.  
Current market sentiment is too bullish, good luck for all the traders. I be observing the market until next opportunity arise 😁.

Hey, mooers!
May has been an exciting month for the market, meme stocks jumped, Dow Jones record high and Nvidia topped $1000 a share after Q1 earnings. Did your portfolio enjoy the heat? Share your investment approach now!
❤️ We'd love to hear:
● Pleasant surprises: How was your monthly performance? Any better-than-expected profit or trading？
● June's investment tactics: Are there any investment plan updates on the horizon?
Event...

He also said that Chapter 20 of The Intelligent Investor is the best chapter ever written on that topic.
Here's what Chapter 20 taught about the Margin of Safety
1. The Concept of a Margin of Safety
A stock has a fair (intrinsic) value based on the underlying company.
This fair value often deviates from the stock price by a wide margin.
No Margin of Safety: Stock Price > Fair Value
Margin of Safety: Stock Pri...

It cause the inflation in the market, better buy equity now before you lose your purchasing power from cash.