Action in financial markets by central banks is usually regarded as intervention rather than participation.
When the principal and interest are added up, it will reflect the amount paid for the user (borrower) of the funds.
However, the term has taken on a specific meaning in finance to describe the particular types of people and companies that regularly purchase equity or debt securities for financial gain in exchange for funding an expanding company.
Less frequently the term is applied to parties who purchase real estate, currency, commodity derivatives, personal property, or other assets.
Speculation, in the narrow sense of financial speculation, involves the buying, holding, selling, and short-selling of stocks, bonds, commodities, currencies, collectibles, real estate, derivatives or any valuable financial instrument to profit from fluctuations in its price as opposed to buying it for use or for income via methods such as dividends or interest.