There are lots of ways a person can leverage funds without selling. For example, assume you have $1,000,000 in your account and are receiving a 10% return, or $100,000 per year in interest and dividends. Assume you want to purchase a home for $500,000 with a downpayment of 20%, or $100,000. All you have to do is pledge $200,000 in stock for your downpayment. You also continue to receive your interest and dividends. In addition you have the interest deduction from your mortgage. If your mortgage is 6% and you are receiving a 10% return, you have arbitraged the funds and are getting 4% on your downpayment.
That's not even done in a margin account. Any major brokerage firm does this.
Investing 103? How the rich get richer...