Design software giant Canva has finalised the first tranche of a share sale it has signalled will reach $3.6 billion, making more of its early staff rich and rewarding investors who had faith in it as a nascent start-up.

The sale was finalised last month at a flat valuation of $US26 billion ($39.4 billion) for the company, with buyers wanting $US2.4 billion ($3.6 billion) in shares but purchasing about $US1.6 billion ($2.4 billion) in that tranche.