What happened

Shares of National CineMedia (NCMI 1.66%) rose 29.6% in May 2018, according to data from S&P Global Market Intelligence. A strong first-quarter report kept this roller-coaster stock chart going with another big turn.

So what

Reporting first-quarter results in the first week of May, National CineMedia saw sales rise 8% year over year while the bottom line swung to a modest profit. Shares closed 16% higher that day.

A movie theater full of smiling and clapping viewers.

Image source: Getty Images.

Now what

The provider of advertising and special event content for American movie theaters sure enjoyed a strong Hollywood spring with blockbuster titles like Black Panther, Jumanji: Welcome to the Jungle, Deadpool 2, and Avengers: Infinity War, all of which are going down in the history books as record-breaking hits. But the company still has to fight a rising tide of high-quality entertainment on the small screen as well as rising ticket prices, making it harder to stay in business with an exclusive focus on the cinematic sector.

That's why National CineMedia's stock chart looks like a rough-cut saw blade, rising when Hollywood delivers advertiser-friendly blockbusters and plunging when that well runs dry again. I don't expect that pattern to change anytime soon, and that's not a good look in the long run from an investor's point of view:

^SPX Chart

^SPX data by YCharts