Twitter soars on takeover chatter, Facebook video views questioned, Yahoo's massive hack

Here are some of the stocks the Yahoo Finance team will be tracking for you today.

Twitter (TWTR) shares soared in early trading after CNBC reported that the social media firm is in talks with potential suitors that include Alphabet’s Google (GOOGL) and Salesforce.com (CRM). The stock was initially lower in the pre-market after RBC Capital Markets downgraded it to underperform from outperform late yesterday amid concerns about Twitter’s advertising revenue based on a recent survey. The firm also cut its price target to $14 a share. That’s a 25% drop from where the stock closed yesterday.

Marriott’s (MAR) stock is in the spotlight after the company completed its $13 billion purchase of Starwood Hotels. Marriott is now the biggest hotel operator in the world. Members of the hotel’s two loyalty programs will be able to link their accounts together starting today.

Facebook (FB) fell in early trading following reports that the company vastly overestimated the time viewers watched video ads on the site. That means advertisers may have have *misjudged* the performance of ads they purchased from Facebook over the past two years. The Wall Street Journal says Facebook overestimated the average time spent watching videos by as much as 80%. Facebook says it fixed the problem, which didn’t affect billing.

Yahoo (YHOO) shares fell this morning after it confirmed that hackers stole information from at least 500 million user accounts in late 2014—including names, phone numbers and some passwords. The company is blaming “state-sponsored” hackers for what may be the largest theft of personal data ever. Yahoo has not found evidence that payment-card data or bank account information was stolen. Yahoo is the parent company of Yahoo Finance.