What happened

Shares of oil and gas driller W&T Offshore (NYSE:WTI) fell throughout April, finishing the month at $2.04 per share, down 26.4%. 

W&T is a small company primarily focused on natural gas liquids production in the Gulf of Mexico. In April, its market cap dropped about $100 million to $280 million. Huge swings like that aren't uncommon for small companies, but what was unusual was the apparent lack of rationale for the drop.

Offshore oil rig under a stormy sky.

W&T Offshore has underperformed the industry over the last ten years. Image source: Getty Images.

So what

There's often some sort of catalyst for a drop like this: a broader market or sector decline, unfavorable industry news, or -- for an energy company -- falling oil or natural gas prices. As you can see from the blue line in the chart below, W&T stock's biggest drop came on April 18:

WTI Chart

WTI data by YCharts

But as you can also see from the S&P 500's line on the chart above, there wasn't a broader market decline on that date. There was a bit of a drop in the overall oil and gas sector, but nothing that would account for the severity of W&T's slide. While other oil and gas producers -- particularly smaller ones -- dropped that day, none fell quite so far.

Nor where there any of the sort of company-specific causes one might expect to induce a big stock plunge: no underwhelming earnings report, no analyst downgrade, no unfavorable news coverage.

There was just one lone news item released by the company on April 18: Thomas F. Getten, the company's vice president, general counsel and secretary, who had been with W&T since 2006, retired and was succeeded by Shahid A. Ghauri. 

It seems inconceivable that such a minor news item could have caused such a pronounced stock slide; it's certainly possible that the timing was just a coincidence. But sometimes even minor news items can have a big impact on small, volatile companies that don't put out a lot of information. So even though it sounds weird, this may have been one of those cases where a piece of minor news had an outsized impact, or just turned a moderate drop into a severe one. 

Now what

Obviously, you shouldn't buy or sell this stock -- or probably any stock -- based on whether the company's general counsel is retiring. But it goes to show that investors in small, volatile companies -- and W&T is both -- may have to stomach wild stock swings that happen with little or no reason.

As for W&T, the company has underperformed almost its entire industry since oil prices started sliding in 2014, losing more than 86% of its value. And given that it cut its dividend to zero in late 2015, there are better and safer places for your money in the oil patch.