Analyst ratings measure the expected performance of a stock during a given time period. Traders and investors should know analysts and brokerage firms often use ratings when they issue stock recommendations to stock traders.

In general, analysts arrive at stock ratings after they research companies’ public financial statements, communicate with executives and customers, and interact with companies in other ways. Amid another busy week of trading, here’s the latest analyst ratings and updates for Plug Power, Roku, Dave & Buster's, and Salesforce.

Piper Sandler analyst Pearce Hammond upgraded Plug Power Inc (PLUG) from Neutral to Overweight and announced a $33 price target. Shares of Plug Power soared higher last week. The clean energy manufacturing company opened Monday’s session at $25.32 and closed Friday higher by 6.52% at $26.97 for the week.

Guggenheim analyst Michael Morris upgraded Roku Inc (ROKU) to Buy from Neutral with a $395 price target. Shares of Roku traded higher last week. The digital media player company opened Monday’s session at $316.84 and closed Friday higher by 1.60% at $321.89 for the week.

Jefferies analyst Andy Barish upgraded Dave & Buster's Entertainment Inc (PLAY) from Hold to Buy and raised the price target from $40 to $56. Shares of Dave & Buster’s climbed sharply higher last week. The restaurant and entertainment company opened Monday’s session at $35.44 and closed Friday higher by 17.33% at $41.58 for the week.

Piper Sandler analyst Brent Bracelin upgraded Salesforce.com, Inc. (CRM) from Overweight from Neutral and increased the price target from $280 to $365. Shares of Salesforce jumped higher last week. The cloud-based software company opened Monday’s session at $256.59 and closed Friday higher by 11.32% at $285.63 for the week.