Book-entry securities are shares, bonds and other instruments held within a book-entry system, in which ownership is recorded as an electronic balance in an account and transferred by debiting one account and crediting another. No paper certificate is delivered to the investor. Almost all publicly traded securities in developed markets are now held in this form.
Securities reach book-entry form in one of two ways. Under immobilisation, a physical certificate, often a single global one for the whole issue, is lodged permanently with a depository and interests in it move by account entry. Under dematerialisation, no certificate exists at all and the electronic record is itself the root of title. In both cases the top-level record is kept by a central securities depository, with custodians and brokers keeping accounts for their clients beneath it.
The term describes the securities; the main entry describes how the accounts, transfers and legal rules operate. The contrast is with certificated holdings, covered under physical securities processing.