I believe the only difference would be whether income is taxable or not. If there is no intended income for this fund -- that is, it's completely prefunded by

I believe the only difference would be whether income is taxable or not. If there is no intended income for this fund -- that is, it's completely prefunded by the founder -- then there's no advantage to jump through the hoops that are necessary to get 403b status. That status is not freely handed out to everyone who walks up and claims their a non-profit. There's quite a bit of work that goes into it.