No that isn't quite right. Any stock can be shorted if the custodian of the underlying holder participates in stock lending programs. That means any stock which has a participating custodian could be potentially shorted - it has nothing to do with UBS nominees being on the register. Just to also clarify, it is not UBS who shorts stocks - it is normally their clients who would borrow the stock and do the shorting.
RFL Price at posting:
26.0¢ Sentiment: Buy Disclosure: Held