US STOCKS-Wall Street slumps as materials, health stocks weigh
* Amazon jumps to record high after posting unexpected profit
* Biogen's fall weighs on Nasdaq, S&P
* Hillary Clinton to propose raising capital gains tax - report
* Visa, Starbucks rise after results
* Indexes down: Dow 0.57 pct, S&P 0.56 pct, Nasdaq 0.32 pct (Updates to early afternoon)
By Tanya Agrawal
July 24 (Reuters) - Wall Street was lower in early afternoon trading on Friday for the fourth straight day as a fall in materials and health stocks and a fall in commodities overshadowed strong results from Amazon, Visa and Starbucks.
Amazon.com shares jumped as much as 20.4 percent to a record of $580.57 after the online retailer posted an unexpected quarterly profit. The jump catapulted Amazon's market value to about $270 billion, overtaking Wal-Mart.
Metal prices hit multi-year lows as weaker-than-expected data from China and the euro zone raised concerns about global growth while oil prices neared four-month lows. Continuación...