According to the article, the issue is not that much tax avoidance as actually paying the tax. A sale would trigger a taxable event and taxes need to be paid from the cash assets. Consulting companies don't have much in cash lying around usually, so that might be an event that could threaten the companies livelihood. Now if you sell to an investor, you receive cash from which you can pay the taxes, but if you "sell" to a trust fund, you don't.