Investors are campaigning for private companies to make theirfinancial information more available in a push for greatertransparency in Europe's growing high-yield bond market.

The Association for Financial Markets in Europe sent a list ofcompanies to bond arrangers on behalf of a group of investors in aneffort to spur debate about corporate disclosure, said GarySimmons, director of AFME's high-yield division. The document namesmore than 75 borrowers they deem too protective of theirdata, with the aim of establishing standardized reporting,according to four people familiar with the matter.

The companies control access to their information by keepingtheir earnings behind password protection, requiring registrationor only emailing their data to stakeholders, said thepeople, who asked not to be identified because discussions areprivate. Demand for better disclosure is intensifying as firmsraise money more frequently in the junk bond market, with issuanceswelling to a record 72 billion euros last year.