The Dow Jones Industrial Average (DJINDICES:^DJI) rose more than 79 points as of 11:30 a.m. EDT. AT&T (NYSE:T) was up 2% to outperform its index, while shares of Solar City (NASDAQ:SCTY.DL) and Twitter (NYSE:TWTR) were also surging

Yellen speaks to the senate
Federal Reserve Chairwoman Janet Yellen was back on Capitol Hill this morning, fielding questions from the Senate Banking Committee. The Dow Jones rose over the course of her testimony, suggesting that investors may have been pleased with her comments.

Yesterday, Yellen was more candid in her comments to lawmakers, saying she doesn't believe the U.S. stock market is in a bubble. On Thursday, she spoke more to economic particulars, discussing topics such as inequality (in her words, "disturbing") and the minimum wage (which she said should have some "negative" effect on the job market).

AT&T gets closer to a DIRECTV merger
AT&T shares rose early on Thursday after reports suggested that DIRECTV was speaking with advisers about a potential merger with the telecom giant.

This news lends credence to recent reports of AT&T's interest in snapping up DIRECTV. Assuming regulators allow it, a merger could better position AT&T to offer a bundle of services -- wireless, paid-TV, etc. -- to its many subscribers.

SolarCity rises after earnings report
Shares of SolarCity were up well more than 19% in early trading. The rally appeared to be prompted by an impressive earnings report. SolarCity reported a loss per share of $0.26 on revenue of $63 million, more than double from the prior year.

SolarCity's earnings report led several firms to upgrade the stock, with J.P. Morgan raising the company from neutral to overweight and Roth Capital giving it a boost from neutral to buy.

Source: Wikimedia Commons.

Twitter up on analyst upgrade
Twitter shares rose 6.4% early after Morgan Stanley upgraded the social network from underweight to equal weight.

Morgan Stanley is still cautious on the name, noting that insider stock selling could continue in the near term after the lockup period expired. But Morgan Stanley doesn't believe that Twitter's earnings, at least in the next few quarters, will disappoint investors.

In general, Twitter may be benefiting from a dead cat bounce. Shares are down about 50% from their all-time high hit in December. Twitter still lacks a price-to-earnings ratio, but some value-orientated investors may have been tempted to buy in light of the recent, aggressive sell-off.

Sam Mattera has no position in any stocks mentioned. The Motley Fool recommends DirecTV, SolarCity, and Twitter. The Motley Fool owns shares of SolarCity. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.