Stocks making the biggest moves in the premarket: Carvana, First Solar, Generac and more

cnbc.com:

Take a look at some of the biggest movers in the premarket:

Carvana (CVNA) – Carvana was downgraded to «sector perform» from «outperform» at RBC Capital Markets, with the price target for the online car seller's stock cut to $138 per share from $155 per share. RBC bases its call both on valuation and potential difficulty in integrating its recent acquisition of car auction company Adesa. Carvana slid 3.4% in the premarket.

First Solar (FSLR) – The solar company's stock fell 4.8% in premarket trading after Bank of America Securities downgraded it to «underperform» from «neutral.» BofA said investors may be overly optimistic about growth prospects and that a new Commerce Department anti-dumping inquiry into Asian module manufacturers is unlikely to drive pricing power.

Generac (GNRC) – The maker of backup generators and other energy-related equipment was put on the «Americas Buy List» at Goldman Sachs. Goldman points to a broad product portfolio, an increasing distribution footprint, and the idea that many of Generac's products are in the early stages of adoption. Generac added 2.1% in premarket trading.

Carnival (CCL) – Carnival rallied 3.6% in the premarket after the cruise line operator said the seven-day period from March 28 through April 3 was the busiest week for new cruise bookings in the company's history.

Twitter (TWTR) – Twitter was up another 1.5% in premarket action after soaring 27.1% Monday. That followed Tesla CEO Elon Musk's disclosure that he had taken a 9.2% stake in the social media company.

Nio (NIO) – Nio gained 1.1% in the premarket following a report in the Financial Times that the China-based electric car maker is speaking with peers about licensing its battery swapping technology.

Farfetch (FTCH) –