What happened

Shares of National CineMedia (NASDAQ:NCMI) rose 22.5% higher in the first half of 2018, according to data from S&P Global Market Intelligence. It was anything but a smooth ride.

So what

The provider of pre-movie advertising services and alternative content distribution for American movie theaters was off to a good start in 2018. The stock climbed 12% higher in late February, goosed by the record-breaking performance of Walt Disney blockbuster Black Panther. Strong box-office sales tend to support rising sales of pre-roll advertising, after all.

But the fourth-quarter earnings report in March fell short of Wall Street's revenue targets, reminding investors that National CineMedia is leaning on Hollywood in a rather fragile era for the movie industry as a whole. Share prices plunged 8% lower in a single day, continued to slide as Wall Street analysts weighed in with their analysis over the next few days, and stayed down until the first-quarter report hit the news wires in May.

That report was a blockbuster, with unseasonably small bottom-line losses and strong revenue. National CineMedia's stock immediately repaired the damage done in March -- and then some. Share prices soared 16% higher that day and the gains expanded to 30% in May as a whole.

A movie theater filled to capacity, showing the logo of National CineMedia's FirstLook service on the screen.

Image source: National CineMedia.

Now what

This stock chart's zig-zag pattern is not new. National CineMedia investors are prone to both positive and negative overreactions when their movie studio clients come up with surprise hits or silver screen disappointments. Investors are currently enjoying a 16% one-year return, right in line with the S&P 500. From a wide-angle perspective, the stock has plunged 46% lower in three years. 2017 was a harsh year for National CineMedia.

So I wouldn't read too much into the stock's gains over this specific time period. Moving your measuring stick around by a couple of months makes a big difference here and the changes tend to be unpredictable. National CineMedia will probably continue to generate sawtooth stock charts for the foreseeable future.