What: Fairmount Santrol Holdings Inc (NYSE:FMSA) endured a September to forget as its stock crashed 42.4% for the month. Fueling the downdraft were three separate catalysts that reared their ugly head last month.

So what: One of the catalysts was the price of oil, which fell 8.5% for the month. Weak oil prices have been a running theme driving down proppant producers like Fairmont Santrol as those weak prices are the cause behind a significant slowdown in oil and gas activity. That's impacting proppant sales volumes and margins.

Amid that weakness, when Fairmont Santrol announced on Sept. 23 that CFO Chris Nagel had resigned to pursue another job it hit the company's stock really hard. While the company said that the departure was, "not the result of any dispute or disagreement with the company or any matter relating to the Company's accounting practices or financial statements," investors still took it as a sign that the CFO didn't want to stick around any longer. The implication was that he didn't see a bright future for the company, which is why there was quite a sell-off right after that announcement.  

FMSA Chart

FMSA data by YCharts

Finally, the overall dour outlook for the proppant industry was reinforced a few days later when one of Fairmont Santrol's peers withdrew its guidance for the rest of the year citing challenging conditions and limited viability. That announcement sent the whole sector spiraling lower.

Now what: It's a troubling time for companies that supply the oil and gas industry as activity levels have cratered. Worse yet, there aren't yet any signs that activity will improve as visibility is very limited. So, with that backdrop, and the fact that its CFO not sticking around for a rebound, Fairmont Santrol's investors did the same as they also bailed on the stock last month.

Matt DiLallo has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.