That's the whole point of the fund--it's invested in things that are not oil. Wikipedia says it's a mixture of equities (60%), government bonds (25%), corporat

That's the whole point of the fund--it's invested in things that are not oil. Wikipedia says it's a mixture of equities (60%), government bonds (25%), corporate bonds (10%) and real estate (5%). If (when) oil profits vanish, these investments will still be there. In fact, since they are legally unable to withdraw more than 4% of the fund's value each year (and typically make more than that), it should continue to grow indefinitely. The fund has a really interesting set of ethical guidelines--they won't invest in tobacco companies, companies causing severe environmental damage, or those involved in nuclear weapons or cluster munitions, for example.