The investing term for borrowing money to increase the size of an investment position is leverage.
Financial leverage uses borrowed funds, or debt, to acquire assets or securities. If the investment rises, the investor's return on their own contributed capital can be amplified because the position is larger. If the investment falls, losses can likewise be magnified, and the borrower still owes the debt and related interest.
Buying securities on margin is one familiar form of investment leverage. A broker lends part of the purchase price, and the investor provides collateral. If the position declines enough, the broker may issue a margin call or sell assets under applicable rules. Leveraged funds and derivatives can create exposure with similar amplification effects, even though their structures differ.
Leverage is not the same as diversification or simply owning an asset. It introduces financing costs, repayment obligations, and possible forced selling. The amount of leverage, collateral requirements, interest rates, and legal protections vary by product and jurisdiction.