The last time I checked (January) all of the HOLDRS are uptick exempt for selling short with the exception of HHH.
Exempt from SEC Rule 10a-1(short sale rule). http://nasdaq.com/structuredeq/holdrs_smh.stm it also says 150% margin on short sale.
Best way to play the SOX, rather than a basket, but best as a swing or intraday trading vehicle. I like the SMH options more. High Risk/Reward. You can get a 2 bagger in a day or two easily. You can also lose 50% in a day as well.