What happened

Shares of Teekay Corporation (NYSE: TK), Teekay Tankers Ltd. (NYSE: TNK), Noble Corporation (NYSE: NE), and Ensco PLC (NYSE: ESV) finished last month down between 8.6% and 9.7% from where they started. Furthermore, they were all down between 9.6% and 13.5% from their peaks in October. In other words, if you bought shares of any of these stocks near their highs in October, you've probably lost money so far.

So what gives? The interesting thing is that there really wasn't any material news about any of these four companies reported in October.

So what

All four of these companies are heavily tied to oil markets. Teekay and its master limited partnership Teekay Tankers operate vessels that transport and store oil and natural gas and related products, while Noble Corp. and Ensco provide offshore drilling services to oil producers.

Image source: Getty Images.

Since oil prices started falling in mid-2016, it's been increasingly more difficult for companies that operate in the offshore oil and gas patch. For drillers Ensco and Noble Corp. and their competitors, it's been especially hard. When the downturn really kicked in during 2015, offshore-oilfield owners began slashing spending for development of new wells.

This has caused a massive amount of disruption in the driller segment, with several major companies filing bankruptcy, almost every other company idling its off-contract vessels to lower expenses, and a huge swath of the oldest drilling vessels being scrapped over the past two years. It has also led to consolidation, such as Ensco's acquisition of Atwood Oceanics, which closed in early October.

For Teekay and Teekay Tankers, the impact has been a little different. The Teekay organization does offer services specific to offshore oil and gas production -- which could be a growth opportunity, as more and more offshore development will be in areas without easy pipeline access. But it also operates a large tanker fleet that transports hydrocarbons from where they are produced or refined to end markets, and this is a low-growth industry that has suffered from overcapacity in recent years.

Now what

For offshore drillers Noble Corp. and Ensco, there is evidence that the worst of the downturn may be over. As Ensco reported in its most recent earnings, the number of new contract awards has increased for each of the past five quarters, and Ensco has won more of those contracts than any other offshore driller.

Noble Corp. added $800 million to its backlog in the third quarter, which it announced in early November. The company has managed to keep its backlog of $3.2 billion essentially flat this year, a notable achievement as many other drillers' backlogs have gotten smaller over the course of the year. The company has also managed to generate positive cash flows this year, while its competitors have had to dip into cash reserves and debt to fund operations.