The collection of all investments held by an individual or institution.
A portfolio is the complete set of investments owned by a person or institution, including stocks, bonds, real estate, commodities, and cash. Portfolio theory suggests that diversifying across asset classes reduces risk without sacrificing returns. Your portfolio's asset allocation (percentage in stocks, bonds, etc.) should match your risk tolerance, time horizon, and financial goals. Rebalancing periodically (annually or when allocations drift) keeps your portfolio aligned with your target. A young investor might have 90% stocks/10% bonds; near retirement, this might flip to 40% stocks/60% bonds. Portfolio performance should be measured against appropriate benchmarks (S&P 500 for stock portfolios, bond indexes for fixed-income).