How do you discount future earnings in times of zero interest rates?

Say you expect a company to make $100B dollars over the next 20 years. What is the value of that?

One might say it is $100B because interest rates are 0.

Not discounting future earnings would make companies extremely valuable. Usually, high P/E ratios are reserved for growth companies. But without discounting, even a company that does not grow at all would be well worth a P/E ratio of 1000. It just has to keep going for 100 years.

What do you guys think?

Use a risk-adjusted discount rate/curve. The published rate is considered risk free. And note that it’s not zero all the way out to longer maturities. To do this seriously look at the curve.