Investors should sell shares in the mega-cap technology stocks that have powered this year's rally in US equities, according to strategists at UBS. But only a few of them.

“We still like many of the largest names,"  the strategists said in a note. "Yet growth is now more expensive and now is a time to also consider rebalancing some mega-cap exposure to other long-term technology themes many of which have been accelerated by Covid-19.”