Friday once again was a letdown for those who had hoped that Dow 20,000 would happen at some point during the week. Stocks gained slightly, but the Dow's rise was limited to 15 points, leaving it 66 points shy of the fabled milestone.

Investors once again seemed sleepy in pre-holiday trading, and major market benchmarks struggled to post even minimal gains in advance of better guidance on what to expect in 2017. Yet even though the markets were mostly flat to up, some stocks performed less well. Sears Holdings (NASDAQ:SHLDQ), GNC Holdings (NYSE:GNC), and Pengrowth Energy (NYSE: PGH) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

Image source: Sears Holdings.

Sears still looks weak

Sears Holdings fell 6%, adding to declines that have taken the stock down by nearly a third so far in December. Many market commentators have noted that the entire retail sector has largely missed out on the stock market's rally over the past month, as nervousness about the state of the U.S. consumer has outweighed long-term hopes about greater prosperity in 2017 and beyond.

In particular, Sears has inspired very little enthusiasm among investors, with losses projected as far into the future as most care to look. There's also evidence that exit strategies will eventually result in the piecemeal dismantling of its remaining business. It's likely that some Sears brands will survive in another form, but pessimism over Sears Holdings stock continues to build during another lackluster holiday season.

GNC gets a bad review

GNC Holdings dropped 11% after getting an analyst downgrade from market pros at Piper Jaffray. The analyst company gave the vitamin and health products retailer an initial rating of underperform, noting that the moves that the ailing retailer has made thus far to try to turn its business around haven't yet produced any meaningful results. In particular, GNC's strategy to sell paid memberships to customers hasn't panned out, resulting in the company reversing course.

Moreover, a recent announcement to buy a Super Bowl ad smacks of desperation in the eyes of some, and Piper therefore lowered its target price on the stock by $4, to $7 per share. Unless GNC can get its act together and reverse its slide, its fundamental business strength is in long-term jeopardy.

Pengrowth gives back some of its November gains

Finally, Pengrowth Energy slid 8%. The Canadian oil company's move contrasted with the performance of oil prices on the day, rising slightly to climb back above the $53 per-barrel level for West Texas Intermediate. Pengrowth is heavily exposed to the oil sands region of Alberta, and higher costs make it crucial for oil prices to remain high in order to support the economics of tapping those challenging resources.

Pengrowth shares had jumped by more than a quarter in late November, when OPEC announced production cuts that led to the belief that crude would stay above the $50 mark for the foreseeable future. However, investors appear to be disheartened by the failure of oil to move above the $50 to $55 range, and that might be contributing to the two-day slide that has cut the share price by nearly 15%.