Ask HN: Why are tech stocks down today?

https://www.google.com/finance?catid=TRBC%3A57&ei=r-c6WcG4AsfQjAGkoY7IBg

Technology sector is down ~2.5% while everything else is mostly flat. It looks like all major tech companies are down ~3-6%. Anyone know what's going on? My searches only bring up articles pointing out the drop but no speculation as to why. Could this be a result of the Comey testimony or the recent UK voting?