* Disney, Viacom lead media selloff
* S&P media index records worst two-day selloff since 2008
* Tesla, Green Mountain fall after results
* Indexes down: Dow 0.72 pct, S&P 0.82 pct, Nasdaq 1.61 pct (Updates to early afternoon)
By Tanya Agrawal
Aug 6 (Reuters) - U.S. stocks slumped on Thursday as a spate of poor earnings reports from media companies dragged the sector index to its worst two-day loss since the financial crisis.
The selloff added to investors' nervousness ahead of a key jobs data on Friday that could provide clues regarding the timing of a rate hike.
Walt Disney's shares fell 5.3 percent to $104.67, a day after their largest daily drop in almost seven years. The stock was also the biggest drag on the Dow and the S&P 500.
Disney lowered profit guidance for its cable networks unit on Tuesday, while Viacom Inc reported lower-than-expected quarterly revenue due to weakness in its cable TV business.
Viacom fell 23.6 percent to $39.28, their lowest in almost four years. Twenty-First Century Fox fell 12.3 percent, while Time Warner, Comcast and CBS were all in the red.
The S&P 500 media index was down 5.2 percent, recording it's biggest two-day fall since November 2008.
"As of now, after Disney all the media stocks are down and it seems people just want to get out of the sector at any cost and take any loss," CLSA analyst Vasily Karasyov said.
"The selling pressure is relentless," he added.
Disney's warning put the spotlights on "cord-cutting", which refers to viewers shifting from cable TV to Internet-based companies such as Netflix. Netflix was up 1 percent at $125.24.
In other earnings-driven stock moves, Tesla fell 10.3 percent to $242.35 and Keurig Green Mountain slumped as much as 30 percent to a two-year low of $52.40 after reporting disappointing numbers.
Even as earnings directed Wall Street's moves on Thursday, investors were jittery ahead of the release of non-farm payroll numbers, which are expected to have risen by 223,000 in July - on par with June.
Economic data released in the last few days have been largely mixed, prompting some investors to argue that the Fed might hold off a rate hike until December.
The Fed has said it will raise rates only when it sees a sustained recovery in the economy. A hike in rates, which have stayed near zero for nearly a decade, will increase borrowing costs for companies, crimping profits.
At 13:27 p.m. ET (1727 GMT) the Dow Jones industrial average was down 126.3 points, or 0.72 percent, at 17,414.17, the S&P 500 was down 17.26 points, or 0.82 percent, at 2,082.58 and the Nasdaq Composite was down 82.76 points, or 1.61 percent, at 5,057.19.
Nine of the 10 major S&P sectors were lower, with the consumer discretionary index's 2.27 percent fall leading the decliners. The index includes media stocks.
In more earnings action, Marathon Oil, Monster Beverage and Zynga report after the close of market.
With about three-quarters of the S&P 500 companies having reported, second-quarter earnings are estimated to have increased 1.6 percent while revenues are projected to have fallen 3.4 percent.
However, valuations look stretched. The S&P 500 is trading at a 25 percent premium to its historical median price-to-sales ratio, Jack Ablin, chief investment officer at BMO Private Bank said in a note to clients.
"The Federal Reserve will soon withdraw its unwavering liquidity, leaving the bulls to rely on technical indicators such the 200-day moving average, above which the S&P 500 is trading."
Michael Kors was among the few bright spots on a gloomy day, rising 11.37 percent to $43.99 after its results beat expectations.
Declining issues outnumbered advancing ones on the NYSE by 1,989 to 1,020. On the Nasdaq, 1,972 issues fell and 771 advanced.
The S&P 500 index showed 16 new 52-week highs and 44 new lows, while the Nasdaq recorded 55 new highs and 155 new lows. (Reporting by Tanya Agrawal; Additional reporting by Lehar Maan; Editing by Saumyadeb Chakrabarty)