A more thorough explanation:

Definition: Portfolio-pumping is a practice in the securities market where an investor buys more shares of a stock towards the end of a fiscal period to make their investment fund's performance look better. This is also known as window-dressing.

Example: Let's say an investment fund has been performing poorly throughout the year, and the fiscal year is about to end. To make their performance look better, the fund manager buys a large number of shares of a popular stock just before the fiscal year ends. This sudden increase in the stock's value will make the fund's performance look better than it actually is.

Explanation: The example illustrates how portfolio-pumping works. By buying more shares of a stock, the investor can artificially inflate the value of their investment fund. This is done to make the fund's performance look better than it actually is, which can attract more investors. However, this practice is unethical and can mislead investors into thinking that the fund is performing better than it actually is.