Most investors are always on the hunt for underpriced stocks. After all, who doesn't love a bargain?

However, not every stock that has taken a tumble is necessarily undervalued. Sometimes, those sell-offs are completely merited even when they hit familiar blue chips. One of our key tasks as investors is to separate the market's mispricings from its correct calls -- and it's not easy.

With this in mind, let's consider the three worst-performing components of the Dow Jones Industrial Average in April. Are any of them bargains after their share price declines, or did Wall Street get it right?

Man stopping a falling chart from falling any farther.

Image source: Getty Images.

What went wrong

April's biggest losers among the bluest of the blue chips were Intel (INTC -5.16%), down 10%; Boeing (BA -2.20%), down 8%; and Amgen (AMGN -1.01%), off by 4%. For perspective, last month the Dow Jones Industrial Average overall gained a little less than 3%.

That trio is a curious mix. Usually, there's at least a semi-clear common thread among the big names logging the worst losses. But, there aren't many similarities between a chipmaker, an aircraft manufacturer, and a pharmaceutical outfit.

There is one common element among these Dow laggards, however: Their recent share price weakness is attributable to disappointing quarterly reports that portend trouble ahead.

Intel's first-quarter numbers weren't terrible. Revenue fell 1% year over year, and operating profits slumped by 6%. Given the challenging, turbulent environment created by the pandemic, however -- and the fact that earnings of $1.39 per share soundly trounced estimates of $1.15 -- those results could be considered a victory.

The small setback was only a taste of the weakness that appears to be on the horizon. Intel is struggling with the same chip shortage most other technology companies are contending with, and is guiding for Q2 revenue of $17.8 billion and per-share profits of $1.05. While that sales outlook is better than analysts' estimates, the bottom-line projection is worse, which indicates its production expenses are rising. The company's full-year guidance suggests its problems will persist for a while.

As for Boeing, the beleaguered maker of passenger jets managed last quarter to deflect some of the impact of the pandemic in a way it wasn't able to navigate its many headwinds a year prior. In Q1 2020, it booked an operating loss of more than $1.3 billion. This past quarter, it whittled the red ink down to just a bit less than breakeven.

The loss was still bigger than analysts had expected, however, and Boeing confirmed in its report that some 737 MAX jets had been grounded (again) due to electrical issues, while deliveries of new ones have been halted until these potential problems can be fixed. The news didn't hit shares especially hard, but it did contribute to what's now nearly a 16% setback from March's peak price.

And Amgen? To the company's credit, its stock is starting to rebound, but that effort has yet to wipe away most of the 7% selloff that hit it last week after the drugmaker not only fell short of Q1's revenue and earnings estimates, but posted lower year-over-year top-and bottom-line numbers due to lower drug prices. And in the current environment, no pharmaceutical company can afford to lose pricing power.

To buy, or not to buy

The $64,000 question: Are these stocks' sell-offs buying opportunities?

Let's consider Intel first. While the worldwide chip shortage is a key reason for its recent weakness, it shouldn't be ignored that rivals Advanced Micro Devices and NVIDIA are now both contenders in the data center space that Intel used to dominate. In fact, its data center sales fell 20% last quarter. While the company is built to last, this competitive headwind won't be quickly or easily overcome. Never mind the chip shortage itself, which remains a bit tough to forecast.

Meanwhile, Boeing continues to talk about a bright future where air travel is robust again, and to be fair, passenger traffic is picking up. It will be years before the business fully recovers to pre-pandemic levels though. In the meantime, the company must deal with another issue involving its 737 MAX jets, which at one point were expected to usher in the next era of passenger travel and fuel optimization. That's another dent to Boeing's credibility that it just doesn't need.

The common element between Boeing and Intel is the one investors can tolerate the least -- uncertainty.

That's not quite the case for Amgen. Sure, its declining pricing power is a concern. As Jefferies analyst Michael Yee pointed out to Reuters though, prices "are typically weakest in the first quarter due to seasonality in patient volumes and then bounce in Q2 on a recovery in buying patterns and patient volumes."

That jibes with a comment made by Amgen CEO Robert Bradway during the company's Q1 conference call: "We felt the impact of the pandemic in January and February, and we began to see a recovery in March, a trend that seems to be holding in April as well."

Throw in this company's reliable growth, a forward price-to-earnings ratio in the mid-teens, and a dividend of just under 3%, and this is the one stock out of these three Dow that I'd say would make for a smart addition to most people's portfolios.