I noticed this security on the London Stock Exchange: Boeing Co. Com Stk USD5 (CDI) (ticker: BOE). What is it exactly? There's "CDI" in its name, so it is a CREST Depository Interest. The issue date is 2004-09-27. Its price seems to track Boeing's stock price on the New York Stock Exchange. However, I could not find any mention of a London listing on Boeing's investor relations website. What could this mean?
Companies usually mention the stock exchanges on which their shares are traded. For example, other prominent CDIs such as Banco Santander S.A. ORD EUR0.50 (CDI) (ticker: BNC) and International Consolidated Airlines Group S.A. ORD EUR0.10 (CDI) (ticker: IAG) are mentioned on their respective companies' investor relations websites. I'm surprised that Boeing did not mention a London listing. Does this mean that someone listed Boeing's shares on the London Stock Exchange without Boeing's permission (similar to unsponsored ADRs in the USA)?