SoftBank Corp has no plans to invest in messaging application Line Corp, Ken Miyauchi, chief operating officer of Japan's No. 3 mobile carrier, told reporters on Friday.

Line plans to hold a media event about its business strategy on Oct.9. That has fuelled some expectations in the banking industry that Line will unveil a strategic alliance with SoftBank and Alibaba Group Holding Ltd after attracting investment from them, the Maeil Business Newspaper reported on Thursday.

A source with direct knowledge of the situation told Reuters in July that Line's parent company Naver Corp was not considering a stake sale to either of the two.

Line, a popular free messaging app, has submitted applications in both New York and Tokyo for an initial public offering, according to sources familiar with the matter.

Investors are closely following developments in the expected offering, which would be the first by a major chat app and which a banking source has told Reuters could value the company at $10 billion to $20 billion.

Banking sources have said the listing would ultimately be either a dual U.S.-Japan listing or a listing only in the United States.

South Korea's Naver has not released any details about the planned listing.