Texas Instruments ( TXN) raised the low end of its second-quarter revenue and earnings estimates after Monday's closing bell. The company now sees earnings of 32 to 36 cents a share in the June-ending period on revenue ranging from $3.28 billion to $3.42 billion. The current estimate of analysts polled by Thomson Reuters is for a profit of 41 cents a share on revenue of $3.35 billion in the quarter. The stock added 2%. Seagate Technology ( STX), the hard drive maker, saw its shares rise 2% after David Einhorn of Greenlight Capital disclosed ownership of more than 23 million shares, or a 5.4% stake, in the company. That's an increase from the 14.5 million shares, or 3.4% stake, that Einhorn disclosed as of March 31. Shares closed up 2.8%. Juniper Networks ( JNPR), the networking equipment maker, announced a new $1 billion buyback authorization. The stock gained 1.3%. Another big mover was Zynga ( ZNGA), which dropped 10% with volume exceeding 55 million, close to three times the issue's trailing three-month daily average churn. The stock fell below $5 for the first time ever with trading triggering a short-sale circuit breaker. The driver was believed to be an analyst report from Cowen saying the company's daily active user activity fell 8.2% last month.