What happened Shares of Seaspan (NYSE: SSW) fell more than 10% on Thursday morning after a Wall Street analyst slapped a sell rating on the shipping company. Seaspan shares had been up more than 60% over the past year, and investors seemed to take the downgrade as a good opportunity to make a profit. So what Seaspan, which owns a fleet of more than 100 containerships, was downgraded to a sell from a hold prior to markets opening Thursday. Analyst Benjamin Nolan said in a note that while market conditions for global shipping have improved, the outlook for global demand does not justify the current valuation. Seaspan container ships. Image source: Seaspan. The Hong Kong-based company has been an active consolidator, buying a fleet of six containerships for $380 million last November and then announcing plans to create a new holding company as part of a $750 million acquisition of APR Energy. Seaspan said the deal would diversify its holdings between maritime and energy, and should generate solid cash flow. But there are some concerns that it will take investors time to grow comfortable with the transformation, and that might have caused some shareholders to head for the exits. Now what It's worth noting that after the initial downturn Thursday morning, the shares battled back as the day went on, closing down less than 4%. SSW data by YCharts But Seaspan shares are still near a multi-year high, with a lot of work ahead of it internally, and mixed signals on the health of the global economy and the long-term outlook for container demand. It is understandable that investors appear skittish at the moment. 10 stocks we like better than SeaspanWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Seaspan wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Lou Whiteman has no position in any of the stocks mentioned. The Motley Fool recommends Seaspan. The Motley Fool has a disclosure policy.Source