Stocks managed their biggest daily gain of the new year today, as a rebound in oil prices helped energy companies push indexes broadly higher. The Dow Jones Industrial Average (DJINDICES:^DJI) gained 227 points, or 1.4%, and the S&P 500 (SNPINDEX:^GSPC) rose by 32 points, or 1.7%.

^INX Chart

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A few companies made dramatic moves lower in spite of the heavy buying volumes today. These underperformers include GoPro (NASDAQ:GPRO) and Best Buy (NYSE:BBY), which both revealed worsening business trends during the just-finished holiday season.

GoPro's fourth-quarter warning
Video-capture device-maker GoPro fell 14% today, which brought the stock's collapse to a stunning 80% since early August. The latest drop came after the company announced surprisingly weak preliminary fourth-quarter results.

Image source: GoPro.

Sales growth slowed during the last few months, diving to just 16%. For context, GoPro posted a 43% revenue gain in the third quarter. At that time, management said that the result reflected surprisingly difficult market conditions.

Things apparently have gotten worse. GoPro's cameras were met with "slower than expected sell through at retailers" during the holidays, the company said today. After accounting for price cuts, returns, excess inventory, and retooling, non-GAAP gross margin is expected to have slumped to 35% of sales from the prior quarter's 47% mark.

Investors will apparently have to wait until GoPro announces its full results on Feb. 3 to hear how CEO Nicholas Woodman and his executive team plan to recover the momentum that the business was enjoying just six months ago -- when it posted 72% year-over-year sales growth and a four percentage-point jump in gross profit margin. In the mean time, we do know that strategy will include cost cuts. GoPro announced plans today to reduce its workforce by 7%, "to better align resources to key growth initiatives."

Best Buy starts shrinking again
Best Buy's 10% drop made it the S&P 500's biggest percentage-point loser after it posted details on its holiday season that showed weaker results than Wall Street was expecting. Comparable-store sales fell by 1.2% during the nine weeks ended on Jan. 2, 2016, while CEO Hubert Joly and his executive team had forecast a slightly better result. A quarter ago, the retailer managed a 1% comps uptick.

Image source: Best Buy.

The main reason behind the return to falling sales was the surprisingly weak performance of the mobile phone category during the holidays, Joly said. Slumping smartphone sales overwhelmed encouraging growth that the retailer booked in other categories, including wearables, home theater, and appliances.

The good news is that Best Buy held the line on pricing, and didn't resort to hefty promotions to keep sales figures rising. As a result, profitability stayed put, rather than falling, as management had predicted in November.

"Despite a slightly softer-than-expected topline," Joly said, "we are improving our fourth quarter operating income rate outlook as a result of our continuing conviction to a disciplined promotional strategy and strong expense management."

Profit improvements aside, investors are looking for steady comps growth as evidence that Best Buy's turnaround plan is gaining traction. Shareholders didn't get that result in 2015, and today's figures don't provide much in the way of positive momentum heading into 2016.