The CNBC survey of 804 Americans around the country was conducted by Hart Research Associates on the Democratic side and Public Opinion Strategies on the Republican side from Oct. 21 to 24. It has a margin of error of plus or minus 3.5 points.

But the results showed that nearly every demographic group — whether age, income or sex — is inclined to think less favorably about Donald Trump 's brand now than before the election. For example, women grew less favorable by a 32 percent to 2 percent margin, and men by a 22 percent to 5 percent margin.

Exclusive new results from the CNBC All-America Economic Survey found that 26 percent of Americans hold a less favorable view of the Trump brand name since the campaign began. Just 4 percent hold a more favorable opinion. Sixty-four percent say their view hasn't changed. Six percent were not sure.

Nothing has come to stand for Trump more than TRUMP: those big and brash golden capital letters that adorn his buildings around the country. But new data suggests his run for the White House could be tarnishing his coveted image.

Several other surveys have suggested Trump's brand has lost some luster in the campaign and there have reports of slashed rates at Trump's new hotel in Washington, D.C., and declines in bookings at his properties.

Among the most troubling aspects from the CNBC poll: negative sentiment toward Trump's real estate holdings, products and hotels has grown among the wealthy, a potentially worrying sign for a business empire that sells luxury. One in 3 Americans earning more than $100,000 saw Trump's businesses as less favorable since the campaign began. Just 4 percent were more favorably disposed. Professionals and managers also grew less favorable on net.

Negative feelings toward Trump's products transcended party lines, though Democrats were much less favorably inclined toward his businesses. Forty-three percent of Democrats found his brands less favorable, compared with 27 percent of independents and 10 percent of Republicans.

Trump voters broke about evenly, with just 5 percent saying they have become more favorable toward the real estate developers brand, and 6 percent saying they have grown less favorable.

Trump himself has responded to such concerns by relying on the old adage that no publicity is bad publicity. If that's true, then the poll may contain some good news for him. Trump's presence on the campaign trail has increased his brand's exposure among a wide range of Americans. Half of the respondents report learning some or a lot more about Trump's properties and products since the businessman turned politician.

Trouble is, the more they know, the less they appear to like. Of those who have learned more about Trump's brand during the campaign, 35 percent say their views are less favorable than they were previously. Just 7 percent say they have grown more favorable toward the brand represented by the big golden letters.