Investing 6 million dollars in stocks requires proper asset allocation and diversification across various asset classes to balance risk and returns. With a large amount like this, it is important to avoid putting all eggs in one basket. A prudent strategy would be to allocate funds across stocks, bonds, real estate, and alternative assets. A 60-40 split between stocks and bonds is a common starting point. Further diversification can be achieved within stocks by investing across market caps, sectors, regions, and factors. Costs and taxes should be minimized to maximize portfolio growth. Partnering with a fiduciary financial advisor can help create a customized investment plan aligned with financial goals and risk tolerance. Patience and discipline are key as the portfolio builds over decades. With the right strategy, 6 million can compound into a substantial sum that generates lifetime passive income.

Diversify across stocks using broad market index funds
A significant portion of the 6 million, say 60-70%, could be allocated to stocks for growth potential. But rather than picking individual stocks, it is best to diversify broadly using low-cost index funds that track the overall market. This provides exposure to thousands of stocks and avoids the risk of betting on just a few companies. The S&P 500 index is a common choice that captures around 80% of the total U.S. stock market capitalization. Combining S&P 500 index funds with mid and small cap funds allows full coverage. Adding international and emerging market index funds provides geographic diversification. Bond index funds can balance risk in the overall portfolio. Within stocks, further diversification can be achieved by holding index funds focused on value, growth, sectors like technology, healthcare, financials etc. Rebalancing periodically maintains target allocation.
Allocate a portion to real estate and alternative investments
The stock market undergoes periodic downturns, hence investing a portion in assets like real estate can provide stability to the portfolio. High quality rental properties that provide steady cash flow are suitable. REITs are another option for liquid real estate exposure. Allocating around 15-20% towards alternative assets like commodities, hedge funds, private equity etc. can enhance diversification benefits and risk-adjusted returns. But due diligence is required as these assets tend to be complex and have higher costs. The key is determining the right mix of stocks, bonds, real estate and alternatives that aligns with your risk appetite and financial goals.
Utilize retirement accounts and optimize taxes
For investing such a large sum, it is critical to utilize tax-advantaged retirement accounts like 401ks and IRAs to grow the funds tax-free over long periods. Annual contribution limits can restrict ability to allocate the full amount but a combination of pre-tax and Roth accounts can provide tax diversification in retirement. Funds that do not fit into retirement accounts can be allocated to taxable brokerage accounts. Tax efficient strategies like tax loss harvesting, asset location, fund placement, charitable trusts, donor-advised funds and others can help optimize after-tax returns.
Work with a fiduciary financial advisor
With 6 million dollars on the line, it is prudent to work with a trusted fiduciary financial advisor rather than investing blindly. The advisor can review your full financial picture and risk tolerance, and construct a personalized investment plan spanning multiple accounts like 401k, IRA, taxable etc. to meet your goals. The plan should have an appropriate asset allocation, utilize the right mix of low-cost index funds, implement tax optimization techniques, and carry out activities like rebalancing and fund placement. Periodic reviews of the plan should be scheduled. This disciplined process can result in superior risk-adjusted portfolio returns.
In summary, investing 6 million dollars in stocks requires spreading the funds across diverse assets utilizing proven portfolio construction techniques. Patience and discipline are key as the power of compounding builds wealth over decades. Partnering with an advisor aligns the strategy with personal financial goals.