The brokerage cut its net profit forecast for NOL in 2012 and 2013 by 7 and 17 percent respectively to factor in weaker freight demand.
However, Credit Suisse said that it sees the price-to-book ratio as 80 percent below its current market price, reflecting weak earnings propects.
Credit Suisse also said Nepture Orient Lines faces competition from cheaper stock options in the sector.
At 0255 GMT, shares of NOL were down 2 percent at S$1.12, and have fallen about 49 percent since the start of the year.