If a recession occurs in 2019, it could spark a 20% decline in stocks.

Brad McMillan, chief investment officer at Commonwealth Financial Network sees the S&P 500 wrapping up 2018 at 3,000, or roughly 3.4% higher than its current level of 2,900.

But in 2019, he's worried about a recession. While it wouldn't be anything as bad as 2008, a few back-to-back quarters of negative GDP growth could spark a bear market in stocks, McMillan said.

A 20% decline from 3,000 would put the S&P 500 at 2,400.

(Editor's Pick. This item originally appeared on Aug. 29.)

 

More from Video

The Final Barrier for One Last Bull Market High

The Final Barrier for One Last Bull Market High

Market Movers: December FOMC Meeting

Market Movers: December FOMC Meeting

Potential Global Market Impacts After the Arrest of Huawei's CFO

Potential Global Market Impacts After the Arrest of Huawei's CFO

Jim Cramer Weighs in on Dave & Buster's Earnings and What It Means for the Mall

Jim Cramer Weighs in on Dave & Buster's Earnings and What It Means for the Mall

Amazon Representative Addresses the Economic Impact of HQ2 on New York City

Amazon Representative Addresses the Economic Impact of HQ2 on New York City