A combination of concerns about the impact of higher interest rates and increased regulatory scrutiny means several fund managers have revealed they are wary of investing in big US technology companies.
The Fang stocks (Facebook, Apple, Netflix and Google), have performed well in recent years but more recently Facebook shares have been flat over the past year to 19 February, at $177 (£126), but fell starkly on 2 February from $193 (£138) to $181 (£129.40) in a single day, and dropped further to $177 (£126), even as the market began to recover.
The shares of Alphabet, the parent company of Google, were $1,093 (£781.70) on 19 February 2017, and are $1,095 (£783.17) today.
Alasdair McKinnon, who runs the £807m Scottish Investment Trust, said he fears the largest technology shares will underperform as bond yields rise.
He said the market has viewed Fang stocks as "sure fire winners" and in a world of abundant liquidity these companies have been among the biggest winners.
But as US interest rates rise and higher bond yields will mean tighter liquidity, this means bad news for investors in stocks such as many of the big technology companies, that do not pay a dividend.
When interest rates are low, Mr McKinnon said the opportunity cost of owning assets that pay no income is low, but as yields on lower risk assets rise, the sacrifice one makes in owning assets with no yield increases, making technology shares less attractive.
Simon Edelsten, who runs the £86m Artemis Global Select fund, said he has been reducing his exposure to technology shares over the past year as he is concerned about the growth prospects for many of those companies.
Mr Edelsten sold his Facebook shares last year as he noted the drop in engagement levels on the site.
He said: "I have never been able to work out a sensible valuation for Netflix although we admire their success.
"Tesla (for what it is worth) we can't value either. And Apple we last owned maybe three years ago when new iPhones had interesting new features (and people needed more memory, which drove upgrades).
"For us this is now very profitable, but probably past it's best growth."
Tom Slater, who jointly runs the £6.8bn Scottish Mortgage investment trust, said the reason he has become slightly less keen on Facebook and Google shares is there are issues these companies have to deal with in terms of their impact on wider society.
He said: "I am not sure the management of these companies understand this in the way they need to for the future."