There are two concepts of marketable securities: broad sense and narrow sense. Broad sense securities include commodity securities, currency securities and capital security.

Securities in a narrow sense are capital security.

Capital security refers to the securities generated by financial investment or activities directly related to financial investment. The bondholders have the right to claim certain benefits from the issuer, including stocks, bonds and their derivatives such as fund securities and convertible securities.

Commodity securities are documents that prove that the holder has the ownership or use right of commodities. Obtaining these securities is equivalent to obtaining the ownership of these cargo waybills, and the owner's ownership of the goods represented by these securities is protected by law. Commodity securities include bills of lading, waybills and warehouse receipts.

Monetary securities refer to securities that enable the holder or a third party to obtain the right to claim money. Currency securities mainly include two types: one is commercial securities, mainly including commercial bills and commercial promissory notes; The other is bank securities, mainly including bank drafts, cashier's checks and checks.