How does one make a perpetual fund?..
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The usual way is to invest in something that pays constant annual interest or dividends greater than annual withdrawals.
If you had $1 million invested in a 5% investment, you could withdraw $50K annually forever and still have $1 million in the account. If you took out less, then you could make up for inflation as well.
I would think that one would be well advised to buy and sell specific investments in harmony with the type of investments that are yielding the best dividends and/or interest, as these vary from year to year.
The Permanent Portfolio, the Merger Fund, several types of government bonds and the Sequoia Fund, as well as an index fund based on the Wilshire 5000 would be a good start.
SEQUX, the Sequioa Fund, seeks to imitate Warren Buffett's Berkshire Hathaway Series A stock.