Trader: Big sell-off coming so buy this...

Traders work on the floor of the New York Stock Exchange.
Brendan McDermid | Reuters
Traders work on the floor of the New York Stock Exchange.

"Halftime Report" trader Joe Terranova fears that after four years without a correction, the S&P 500 is overdue for a significant pullback.

Here's why and what he's doing about it in the show's portfolio competition.