Software house Atlassian has beefed up its initial public offering, making more shares available at a higher price range.

Under the new deal, Atlassian is now offering 22 million shares at a price range of US$19 to US$20 each (A$26.16 and A$27.53).
Atlassian could now raise between US$418 million and US$440 million.
The company originally offered 20 million shares at US$16.50 to US$18.50 each. At the middle of the range, the company expected to raise US$350 million.
At the new US$19.50 per share midpoint, the upgraded offering values Atlassian at US$4.1 billion.
Atlassian, which is based in Sydney, makes corporate collaboration software, bug tracking tools and chat apps.
The company's founders, Mike Cannon-Brookes and Scott Farquhar, have been pitching to US investors for the past week.
Atlassian is expected to debut under the ticker code TEAM on the Nasdaq later this week.