[U.S. Memory Chip Stocks Strengthen Pre-Market, SanDisk (SNDK.O) Up 3.5%] According to Golden Finance, on May 13, U.S. memory chip stocks strengthened pre-market, with SanDisk (SNDK.O) up 3.5%, Micron Technology (MU.O) up 5.2%, Western Digital (WDC.O) up 3.5%, and Seagate Technology (STX.O) up 2.9%.