Top trader Najarian: Buy this chemical stock

Axiall Corporation
Source: Axiall Corporation

In hopes of making a comeback in CNBC Pro's model portfolio competition, "Halftime Report" trader Jon Najarian bought shares of a chemical manufacturer on Thursday.

Najarian's model portfolio is up nearly 9 percent this year in the competition, which he had once led with a double-digit return.

After spotting unusual activity, the options trader got behind Axiall Corporation, which makes chemicals that are used in a wide array of consumer products.

Axiall's stock rallied 29 percent this year, recovering from a 52-week low set in October.

Here's how Najarian is positioning his portfolio for an even bigger move.