Ticker: CMG

Sector: Services

52-Week Performance: -10.4%

Comment: Chipotle was rocked by a pork shortage after some of its suppliers violated its strict standards. And then an E. coli outbreak linked to its restaurants in at least six states forced the restaurant to close more than 40 stores as well as issue apologies on TV and in newspapers. 

Chipotle later warned that future sales may drop significantly if health authorities continue to investigate.

Ticker: VRX

Sector: Healthcare

52-Week Performance: -13.48%

Comment: Valeant's troubles really kicked off after a brutal report from short-selling firm Citron Research that called the company the "pharmaceutical Enron." The stock crashed more than 20% that day and struggled to regain its composure afterwards. 

Valeant ended up cutting ties with Philidor, the specialty pharma at the center of Citron's allegations that Valeant was using shell pharmacies to record ghost revenues.

Ticker: SWHC

Sector: Industrial goods

52-Week Performance: +134%

Comment: Gunmakers had another very profitable year as the gun-control debate got more intense after several tragedies. Smith & Wesson even acknowledged in its annual report that demand for its firearms had spiked since President Barack Obama took office in 2009.

The risk of tighter gun laws in the future drove people to buy.

Ticker: KBIO

Sector: Healthcare

52-Week Performance: +78%

Comment: KaloBios shares rocketed 400% after Martin Shkreli and other investors gave the company an investment lifeline and he was named CEO. The stock then crashed about 50% before being halted on the day the FBI arrested Shkreli on charges of securities fraud.

Earlier this year Shkreli made headlines after his other company, Turing Pharmaceuticals, raised the price of one of its drugs by 5,000% overnight. 

Ticker: TWTR

Sector: Technology

52-Week Performance: -31%

Comment: Twitter struggled to get people to sign up to tweet and so its monthly active users trailed analysts' expectations. Then-CEO Dick Costolo resigned, leaving a leadership vacuum for a few months that made investors worried about the company's future. Nerves weren't completely calmed when co-founder Jack Dorsey took over, as he also happened to lead Square, a public company.

And of course, we won't forget when Selerity leaked Twitter's earnings after they were apparently released too soon. 

Ticker: BABA

Sector: Technology

52-Week Performance: -20%

Comment: Barron's published a 3,000-word article on why we should all doubt the integrity of Alibaba's financial statements, and argued that the company's stock could fall 50%. A number of analysts thought some of Barron's points were overblown. 

Ticker: YHOO

Sector: Technology

52-Week Performance: -31%

Comment: Yahoo CEO Marissa Mayer continued to try, but struggled, to turn around the tech giant and put it on par with Google, Facebook, and the like.  

Yahoo bailed on its plan to spinoff its $30+ billion Alibaba stake after pressure from the activist hedge fund Starboard made it clear there could be a huge tax hit if the "tax-free" spin-off didn't go to plan. 

Ticker: IONS (formerly ISIS)

Sector: Healthcare

52-Week Performance: 8%

Comment: After the Paris terror attacks for which ISIS claimed responsibility, this $7 billion biotech company with the same name started thinking seriously about a name change, eventually changing its name to Ionis Pharmaceuticals.

Isis Pharma had been named after an Egyptian goddess of health.

Ticker: LL

Sector: Services

52-Week Performance: -69%

Comment: This was probably the biggest consumer-safety story of the year. In March, a "60 Minutes" investigation uncovered the alleged use of excessive formaldehyde in Lumber Liquidators' laminate flooring sourced from China. The company said the program had used an improper testing method and then went ahead to pull the affected flooring.

In the aftermath, a number of senior executives including CEO Tom Sullivan resigned and the stock got punished.

Hedge fund manager Whitney Tilson, who helped blow up the allegations, covered his short bet in December. 

Ticker: CAT

Sector: Industrial Goods

52-Week Performance: -21%

Comment: The ugly chart of Caterpillar's monthly sales got worse as sales continued to fall every month into a third straight year. China's transition to a consumer-based economy from an industrial-based economy hurt sales of construction equipment. 

Ticker: LNG

Sector: Basic Materials

52-Week Performance: -38%

Comment: Billionaire activist investor Carl Icahn took an 8.18% stake in the company and said its shares were cheap. The company has not been profitable for two decades and eventually, CEO and co-founder Charif Souki was voted out of power by the board in December. 

Ticker: WMT

Sector: Services

52-Week Performance: -25%

Comment: Walmart sent shockwaves through the retail industry in October when it lowered its outlook for future profits, citing investment in employee wages and training. The company is also at the intersection of shifting consumer habits which have seen online sales — and Amazon's stock price — benefit as a result. 

Sector: Services

52-Week Performance (S&P 500 Media Index): 2%

Comment: Investors got spooked by the fact that cable subscriptions are declining in favor of streaming and on-demand services. Among the big losers during an August sell-off were Viacom, CBS, and Disney, with Disney's ESPN serving as the single-most interesting media property of 2015. 

Companies: Facebook (FB), Amazon (AMZN), Netflix (NFLX) and Google (GOOGL). Nike (NKE), O'Reilly (ORLY), Starbucks (SBUX) and Home Depot (HD).

Comment: These stocks basically held up the S&P 500 and accounted for more than all the gains the index had. In a year where the broad indexes were more or less flat and a number of individual stocks got hammered, it was a few names with some catchy nicknames that captured investors' attention. 

Ticker: MCD

Sector: Restaurants

52-Week Performance: 37.40%

Comment: In January, then-CEO Don Thompson retired and was replaced by Steve Easterbrook, who unveiled a massive turnaround strategy to plug the leak in sales.

Some of the big changes this year included 100% sirloin burgers, build-your-own burgers, self-serve kiosks, nationwide mozzarella sticks, and all-day breakfast. 

Sector: Services

Comment: Retailers like Macy's, Nordstrom and JC Penney reported tanking sales towards the end of the year, and blamed the weak numbers on everything from warmer-than-normal weather to lower traffic at malls. 

Ticker: SUNE

Sector: Solar Technology

52-Week Performance: -66%

Comment: Hedge funds that bet big on this stock, including Greenlight Capital and Omega Advisors, got slammed as the stock plunged. Investors were looking into its debt obligations and cash commitments and didn't like what they saw.

Ticker: AVP

Sector: Consumer Goods

52-Week Performance: -53%

Comment: The stock went nuclear after someone filed a bogus buyout offer for the company on the SEC's website. The SEC filed a lawsuit against a number of firms and Nedko Nedev, a 37-year old trader with an address listed in Bulgaria.

And after initially declining to comment on reports of a buyout offer, we learned that Cerberus Capital Management took a majority stake in the cosmetics company's North America business in mid-December.

Here's what Wall Street is predicting for the stock market in 2016 »