The heat Nike has taken over its controversial advertising campaign featuring former NFL star Colin Kaepernick seems to have had another effect: burnishing the iconic brand's appeal to investors.

Nike shares have surged 36 percent on the year, making the company the top performer on the Dow's index of 30 blue-chip stocks. The run-up includes a nearly 5 percent increase since Nike's Labor Day announcement that Kaepernick would be featured in its campaign, adding nearly $6 billion to the company's market value.

The stock continues to hover near an all-time high, which it reached in mid-September only weeks after some Nike customers publicly burned their shoes to express their displeasure at the new ad.

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In afternoon trading Nike shares were up slightly to $85.67.

For Nike, the boost eases concerns about the decision to link its brand to the controversial Kaepernick, who in 2016 started kneeling during the national anthem before games to protest racial injustice.

Nike knows its consumer base, which skews younger, said Art Hogan, chief market strategist at B. Riley RBR. "I don't think they just randomly decided to put this ad out, thinking, 'Let's commit political-correctness suicide'."

"People vote with their wallets, and the one clear winner in athletic apparel remains Nike," he said, comparing Nike to Apple in its ability to create demand by rolling out "must-have" products.

Nike did not return a request for comment on Kaepernick's compensation or whether it might be tied to the company's stock performance. But various media accounts peg his pay at millions a year, not bad for a football player no longer playing in the professional ranks.