As an investment tool, securities investment fund gathers the funds of many investors, and is managed by fund trustees (such as banks) and professional fund management companies, so as to achieve the purpose of income by investing in stocks, bonds and other securities.

According to whether the fund can be redeemed, securities investment funds can be divided into open-end funds and closed-end funds. Open-end fund refers to an investment fund whose scale is not fixed, but which can issue new shares or be redeemed by investors at any time according to market demand. Closed-end fund is relative to open-end fund, which refers to the investment fund whose fund size has been determined before issuance and remains unchanged within the specified period after issuance.

2. National debt

The so-called national debt is the debt borrowed by the state, that is, national debt, which is a written loan certificate issued by the state to investors to raise funds, and promises to pay interest on schedule according to the agreed conditions within a certain period of time and return the principal at maturity. According to the par form of national debt, it can be divided into three categories, namely: bearer (physical) national debt, voucher national debt and book-entry national debt.

3. stocks

Stock is a stock issued by a joint stock limited company to investors when raising capital. Stock represents the ownership of its holder (that is, shareholder) to a joint-stock company. This kind of ownership is a comprehensive right, such as attending the shareholders' meeting, voting, and participating in major decisions of the company. Receive dividends or share dividends, etc. Every stock in the same category represents the equal ownership of the company. The share of ownership of the company owned by each shareholder depends on the proportion of shares held by each shareholder to the total share capital of the company. Generally, stocks can be traded and transferred with compensation, and shareholders can recover their investment through stock transfer, but they cannot ask the company to return their investment. The relationship between shareholders and the company is not a creditor-debtor relationship. Shareholders are the owners of the company, and are limited by their capital contribution, taking risks and sharing profits.