[Philadelphia Semiconductor Index Turns Negative After Rising About 5%] BlockBeats News, July 31, according to BIT (bit.com) market data, the Philadelphia Semiconductor Index turned negative after previously rising about 5%. SanDisk (SNDK.O) fell about 7%, Micron Technology (MU.O) dropped over 4%, and SK Hynix (SKHY.O) declined more than 2%.