Japanese giant Softbank is planning to list its mobile phone business in Tokyo and overseas, according to the Nikkei newspaper.
The listing on the Tokyo Stock Exchange and possibly in London aims to raise 2 trillion yen ($18bn; £13.1bn).
Softbank confirmed in a statement that the share sale is an option but no decision has yet been made.
If it goes ahead, the stock market listing would be one of Japan's biggest initial public offerings.
The Softbank Group reportedly intends sell about 30% of the outstanding shares in its subsidiary to investors, while keeping a stake of around 70%.
The firm is considering raising funds from overseas investors, possibly via a stock market listing in London
"We are always studying various capital strategy options", the statement said.
"The listing of SoftBank Corp. shares is one such option, but no decision has been made to officially proceed with this course".
According to the Nikkei, the share sale could rival that of Nippon Telegraph and Telephone in 1987.
SoftBank would use the proceeds to invest in growth, such as buying into foreign information-technology companies, the Nikkei said.
The Japanese telecommunications giant is one of the world's biggest technology companies and is run by its founder, Japanese entrepreneur Masayoshi Son.
It has previously acquired Vodafone's Japanese operations and the US telecoms company Sprint, reports BBC.
In 2016, Softbank bought UK technology firm ARM Holdings for $24bn ($32bn)..