The stock market posted substantial gains on Monday, sending the Dow and S&P 500 up about 2%. Investors apparently celebrated the resolution of the FBI's investigation into newly found email communications and the removal of some uncertainty about the 2016 presidential election campaign. Yet even though the stock market did well, some stocks fell sharply, and EarthLink Holdings (NASDAQ: ELNK), Barrick Gold (NYSE:GOLD), and GoPro (NASDAQ:GPRO) were among the biggest decliners on the day. Below, we'll look more closely at these stocks to tell you why they didn't join the rally today.

Image source: EarthLink.

EarthLink reports results, agrees to merger

EarthLink Holdings fell 10% in the wake of two key pieces of news. The company released its third-quarter results, which included weaker bottom-line performance than investors had expected. Yet the bigger news came on the mergers and acquisitions front, where EarthLink said it had agreed to buy Windstream Holdings (NASDAQ:WINMQ) for $1.1 billion in stock and assumed debt. Under the deal, EarthLink shareholders will receive 0.818 shares of Windstream for every EarthLink share they own. Investors appeared underwhelmed by the terms of the buyout, and EarthLink gave back almost all of the ground it gained on Friday when news of a potential combination got out. Windstream shares were essentially unchanged, suggesting that investors think that the telecom got the better end of the deal.

Barrick tarnishes as the gold market sags

Barrick Gold dropped 5% on a tough day for gold mining stocks in general. First, the price of gold bullion plunged in response to the apparent reduction of risk levels in the financial markets. Gold prices were down $23 per ounce to $1,282, giving back a sizable portion of its gains from last week. In addition to that immediate impact on Barrick, investors also believe that the likelihood of a Federal Reserve interest rate increase could be higher than previously thought. That would be further bad news for gold investors who rely on financing to take positions in the bullion market, and combined with the drop in bullion prices, it goes a long way toward explaining what's happening with Barrick and other gold stocks today.

GoPro gets a downgrade

Finally, GoPro lost about 5%. The maker of camera equipment for the action-sports market received a downgrade from Merrill Lynch, which cut its rating on GoPro to underperform and reduced its price target to $10 per share. Concerns about GoPro's ability to manufacture enough of its Hero 5 cameras to meet demand could hit the company's fourth-quarter results, and any failure to keep up with customers' needs could drive an overall defection away from the industry. Going forward, GoPro will have to demonstrate strong demand not only for its Hero5 cameras but also for the new Karma drone product in order to satisfy investors that the company is on the right track for long-term growth.

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