Transocean Ltd. (RIG)

[Timothy Smith]

Transocean (RIG -5.8%) says the oil drilling sector is enduring the most challenging market in 30 years, but the industry's cyclical nature ultimately will yield a recovery and drive demand for its assets and services.

In a letter to shareholders, RIG touts a strong portfolio of drilling rigs, with two new ultra-deepwater rigs added to its asset base; both rigs are under a 10-year contract for Shell, with a third, tapped for Chevron, is scheduled for later this year.

The company says results from 2015 were better than it expected, but moving through the weakened oil market landscape presents significant challenges for the year ahead.