The company, called 21st Birthday, will be sold to a Chinese company.
Photo: Alex Ellinghausen 21st Birthdays has a long history in Australia.
In 2014, it was purchased by a group of Chinese investors and rebranded as 21st, according to the company.
A spokeswoman said the sale had been approved by the Australian Securities and Investments Commission.
A spokesman for 21st birthdays declined to comment.
In 2016, the company said it would no longer sell its jewellery.
It said it had been unable to find a buyer.
“While we have a long-standing relationship with the Australian community, we will no longer be selling our jewellery to Australian consumers,” it said in a statement.
“We believe it is important to provide a safe and secure alternative to traditional brands.”