This tech company has just had a shocker over on the US markets. Atlassian shares last closed at US$174.17 each. But that was during normal trading hours. Its after-hours performance was far bleaker. In after-hours trading, Atlassian shares were down a horrible 22.6% to just UD$134.73. That would be a loss of close to US$10 billion in market capitalisation. Ouch.