Key takeaway — Diversification reduces concentration in specific risks, while rebalancing restores the portfolio when market movements push it away from the intended risk level.
Reviewed August 20, 2026. Tax, pension, mortgage, and guarantee rules can change; verify the current official rules before applying, signing, or transferring money.
1. Diversification is not designed to maximize the best-case return
Its purpose is to reduce the chance that one company, sector, or risk factor dominates retirement security. Investor.gov emphasizes diversification both across asset classes and within them.
2. Retirement does not eliminate every type of risk
All-cash portfolios can reduce price volatility but may face long-term inflation and purchasing-power risk. Too much exposure to volatile assets can create a different problem when withdrawals are required during a decline.
3. Rebalancing is not performance chasing
If a market rally pushes the stock allocation far above the intended level, rebalancing may involve reducing that exposure or directing new money to underweight assets to restore the original risk profile.
4. Use a pre-defined review rule rather than constant trading
Investor.gov describes calendar-based reviews or reviews triggered when allocations drift beyond a chosen threshold. Fees and tax consequences matter, so rebalancing does not need to become daily activity.
Official sources
- U.S. SEC Investor.gov — Asset Allocation and Diversification
- U.S. SEC Investor.gov — Investor.gov Tips for 2026
Money & Why note: This is general educational information, not an individualized buy/sell instruction, guaranteed return, or legal, tax, or investment advice. Apply the framework to your own income, debt, taxes, family situation, and time horizon.