After the President blasted Nordstrom (JWN) in a tweet Wednesday morning condemning the retailer’s decision to stop selling his daughter Ivanka Trump’s brand, Nordstrom stock did something nobody expected: It surged.

In what some on Wall Street are declaring the stock trader’s answer to a political protest, Nordstrom stock barely flinched at President Trump’s criticism, dipping less than 1% before aggressively reversing course, ending the day up more than 4%.

Nordstrom’s stock price reaction runs opposite to that of other Trump tweet targets, including Lockheed Martin (LMT), whose shares fell 2.5%—initially swooning as much as 4%—in December when the President tweeted that its F-35 fighter jet costs were “out of control.” Trump’s tweet last month threatening Toyota (TM) with a border tax if it persisted with its plan to manufacture cars at a new plant in Mexico also swiftly tanked the automaker’s stock, which closed down 0.6% that day.

But investors were hardly fazed when President Trump decried Nordstrom for treating Ivanka “unfairly,” calling the department store “terrible” in a tweet just before 11 a.m. Wednesday.

My daughter Ivanka has been treated so unfairly by @Nordstrom. She is a great person — always pushing me to do the right thing! Terrible!

— Donald J. Trump (@realDonaldTrump) February 8, 2017

Traders exalted in their newfound ability to overpower the President’s market-moving attacks, perhaps for the first time. While other stocks targeted in Trump’s tweets since he won the Presidential election, such as Boeing (BA) and General Motors (GM), have recovered the same day, none have had as big of an upward bounce as Nordstrom. Twitter (TWTR) sentiment as measured by Bloomberg, which has been shown to correlate with stock prices, spiked negative on Nordstrom only very briefly before increasingly tipping positive in the afternoon.

Some investors said they even purchased more Nordstrom stock to show their support of the retailer, after it confirmed it was dropping the Ivanka Trump clothing line. One trader dubbed the Nordstrom stock movement a rebellion, tweeting, “The #Trump Protest, now on Wall Street.” Another Twitter user Kathryn Cramer, a writer and apparent retail investor, tweeted that she “bought 25 shares in solidarity.”

$JWN: Protest via stock purchase

— Jeff (@BeastQuake) February 8, 2017

The #Trump Protest, now on Wall Street.

Traders "rebelled" against Trump's tweet in attempt to hurt the share price of $JWN pic.twitter.com/pckGDN98Fe

— The Daytrade™ (@d4ytrad3) February 8, 2017

There is, however, another explanation for Nordstrom shares’ counterintuitive reaction. About eleven minutes after Trump’s tweet, the National Retail Federation announced its 2017 industry forecast, anticipating retail sales would grow as much as 4.2% over last year. The optimistic outlook juiced the stocks of retailers including Macy’s (M), which rose 2.5%; Under Armor (UAA), up 3%; and J.C. Penney (JCP), up 5%. Still, Nordstrom’s stock’s gain far outpaced the broader industry, with the S&P Retail Select Industry index rising only about 1.3%.

Just before the market closed Wednesday, Nordstrom itself weighed in to protest the White House’s account of the incident, after press secretary Sean Spicer doubled down on the President’s criticism of the retailer. Explaining its justification for no longer carrying the Ivanka Trump brand, a Nordstrom spokesperson said its decision was based on poor performance of the line over the past year, especially in the latter half of 2016. “Sales of the brand have steadily declined to the point where it didn’t make good business sense for us to continue with the line for now,” the Nordstrom spokesperson said in a statement, adding that it had “personally informed” Ivanka of the decision early this year.

Besides politics, one other theory may account for Nordstrom stock’s ability to shrug off the President: Investors have simply stopped taking his tweets as seriously as they once did.