Final answer:
An investor with a high tolerance for risk should diversify the portfolio by investing in different sectors.
Step-by-step explanation:
When faced with significant losses in their stock portfolio, an investor with a high tolerance for risk should diversify the portfolio by investing in different sectors. Diversification involves spreading investments across different sectors to reduce the impact of any single stock's performance on the overall portfolio. This strategy helps mitigate risk by balancing out potential losses with potential gains from other investments.