Tax Considerations in Portfolio Management for Private Wealth

John is a 40-year-old software engineer who has accumulated a substantial amount of wealth over the years. He currently holds a diversified portfolio consisting of stocks, bonds, and mutual funds. As part of his financial planning, he is considering various tax strategies to enhance his after-tax returns.

Discuss two tax considerations that John should evaluate in managing his portfolio. Include the impact of capital gains tax and tax-efficient investment strategies in your response.