The "buy-and-hold" investment strategy involves purchasing stocks or other assets and holding onto them for an extended period, regardless of market fluctuations. This approach is based on the belief that, over time, the value of investments will increase, allowing investors to benefit from long-term growth. Investors who use the buy-and-hold strategy typically focus on the fundamentals of the assets they choose, such as the performance of the company or the overall market trends. This method can reduce transaction costs and minimize the stress of trying to time the market, making it a popular choice among retail investors and financial advisors.