While it canāt paint a complete picture PE is perhaps the simplest way to measure optimism / gauge how expensive something is.
PE tells you how much you have to pay for a yearās earnings.
If there are 2 machines that make a Ā£1 coin every year
- A is very good, itās very reliable and in future it might make them even faster
- B is a bit dodgy, itās getting slower and thereās a chance it might break entirely
People might be willing to spend Ā£100 on A but only Ā£10 on B because itās riskier. A has a PE of 100, B has a PE of 10
A high PE generally implies that the market is expecting earnings to increase in future hence investors are willing to pay a significant premium for the current earnings.
A low PE means the market is looking less favourably and is therefore unwilling to spend so much, they expect to recoup their investment sooner as maybe they have a less optimistic outlook in the longer term.
I think E/P āEarnings Yieldā (instead of P/E) is a more intuitive way of thinking about the exact same thing. Very simplistically you can compare this to the interest rate on a bond.
Intel has a P/E of 13.2 or E/P of 7.6%
Apple has a P/E of 35.5 or E/P of 2.8%
Tesla has a P/E of 1101 or E/P of 0.09%
Clearly no one would risk their money for 0.09% yield (when you could get more for a ārisk freeā government bond) so they must be anticipating massive growth and are willing to look a very long way into the future.
Conversely 7.6% is very good in the current climate, so investors must be anticipating some decline or risk making them unwilling to look so far ahead and earn their money back sooner.
Investopedia has lots of definitions / explanations for investing & finance terms: