Tripped on Trump: The stocks that have reversed course since the election

More than a third of stocks on the S&P 500 have missed out on the "Trump bump" lifting the overall market since Election Day.

Not everyone is in the money from the "Trump bump" on stocks, which has seen the S&P 500 rise more than 3 percent since the election.

More than a third of companies in the index have dropped in the period, according to a CNBC analysis. The losses have been led by utility companies and consumer staples, with both sectors down more than 4 percent. On top of that, uncertainty over the future of the Affordable Care Act has sent health care stocks down, continuing a 2016 trend.

The topsy-turvy market dynamics following Donald Trump's election were as unexpected for some market observers as the election itself.

At least a few advisors upgraded consumer staples immediately following the election, saying the sector could provide some stability during an unsure period. Instead, stocks in the sector are down 4 percent on average, led by Tyson Foods (down 19 percent since Election Day), Coty (-16 percent) and Mondelez (-11 percent).

Then there is a rare set of companies that had seen positive years turn negative in the aftermath of the election. Those 19 stocks have seen such a drop in the past few weeks that they erased all the gains of 2016. The disparate names make clear that it's a stock picker's market.

Unhealthy earnings

Uncertainty around the future of the ACA, a pillar of the Obama administration, has investors concerned about health-care stocks. Trump has spoken of the need to dismantle and repeal the law. Experts have said it would be difficult to do away with Obamacare completely without causing havoc.

Managers at some health-care companies have expressed their own doubts while others have maintained that their firms are well-positioned to weather the storm.

Of the "Trump losers," Minnesota-based Patterson Companies has seen the biggest drop in share price since the election, around 16 percent. The dental and veterinary supply company was up over 3 percent since the end of 2015 but fell in November following a lackluster third-quarter earnings report.

Medtronic, too, has seen a growth year turn sour. The medical device company missed analysts' second-quarter 2017 revenue forecasts by $108 million in November. The company's revenue of $7.345 billion was the weakest growth in five years, according to a Guggenheim Partners research note.

Still, Chairman and CEO Omar Ishrak expressed optimism about the company's future on a Nov. 22 conference call: "A move towards value-based healthcare, a move towards a regime where the entire healthcare market gets rewarded for producing better outcomes will not only lower costs, but that it's the only way forward," he said.

Other factors

Of course, Trump isn't the only thing happening in the market: Fickle consumers, OPEC's move to curb oil production and troubled economies around the world continue to increase volatility.

Activision Blizzard beat analysts' estimates in early November with earnings of 52 cents per share and revenue of $1.6 billion in the third quarter, but the stock has still fallen in recent weeks. The market's biggest video game company, Activision is behind franchises like "Guitar Hero," "World of Warcraft" and the massively popular "Call of Duty." The release of "Call of Duty: Infinite Warfare" in November was widely panned by critics.

Kellogg posted earnings of 96 cents per share for Q3 in early November, beating street estimates by 9 cents. But revenue fell 2.2 percent to $3.25 billion, and the company lowered its full-year sales growth forecast to 4 percent. The food manufacturing company has been targeted with a boycott for pulling its advertising from the far-right news and commentary site Breitbart.

As CNBC has previously reported, Kellogg's management has cited the Venezuelan economy as a weak spot in its operating profits. Mondelez, another food company, has also suffered from Venezuela's economic instability and has seen its 2016 gains vanish since Election Day.