This artice about Atlassian gives an insight into why companies like Nearmap are being shorted https://www.canberratimes.com.au/bu...giant-nobody-understands-20180907-p502dy.html
"And, like many tech companies whose shares look expensive on traditional measures, it has also been targeted by short sellers. About 7 per cent of Atlassian's free float has been sold short, according to Bloomberg."