3 drivers of the stock market's bull rally are hitting extremes and point to lower returns ahead, economist says

Adobe Firefly, Tyler Le/BI

• Stock market gains will slow as key drivers like valuations and rates hit extremes, David Rosenberg said.
• He said operating earnings would need to surge to fuel further market gains.
• "There are few drivers left to keep the equity party going," Rosenberg said.

The main drivers of significant stock market gains over the past three decades are nearing extremes, suggesting future returns will be significantly lower.

That's according to economist David Rosenberg...