Afterpay Touch Group Ltd (ASX: APT) shares have been like gold on the ASX in the past 2 years. Since listing in June 2017, the group's share price is up 885.76% to $29.08 per share.
It's been a similar story for fellow WAAAX tech stock WiseTech Global Ltd (ASX: WTC).
The WiseTech share price has rocketed 522.19% higher since April 2016 and is rightly considered a top performer.
That hasn't been the case this week though, as Afterpay and WiseTech shares have slumped 7.94% and 8.54% lower, respectively.
Why are Afterpay and WiseTech shares getting hammered this week?
It has been relatively smooth sailing for both Aussie tech companies so far this year.
Afterpay shares are up 142.33% even with this week's slump, while WiseTech has delivered a tidy 46.51% in 2019.
The big change this week, however, has been the United States trade threats.
The S&P/ASX 200 (INDEXASX: XJO) lost $45 billion or 2.19% on Tuesday and backed that up with a 1.6% decline on Wednesday.
US President Donald Trump has been threatening more tariffs on many nations around the world, and even many allies have not been spared.
The US has slapped tariffs on a number of key goods while also putting steel and aluminium tariffs on South American allies such as Brazil and Argentina.
This has stoked fears of retaliations around the world and a potential economic slowdown as a result of the tensions.
For companies with operations in the United States, such as Afterpay and WiseTech, this could hurt potential earnings.
As a result, Afterpay and WiseTech shares have slumped 8% lower across the week.
What about the other WAAAX stocks?
Appen Ltd (ASX: APX) shares have been under pressure this week as well and are down 7.39% to $22.68 per share.
The Altium Limited (ASX: ALU) share price has edged 1.67% lower this week but is still up 63.12% for the year.
The big surprise for me this week has been Xero Limited (ASX: XRO). The cloud-based accounting group has been relatively steady while its WAAAX peers have fallen around it.
Xero shares closed 1.50% higher on Wednesday to be in the top 5 ASX 200 gainers.
