[hathathat]

If the CEO wants to buy a new Ferrari, they need to take money out of the company - either as income or dividends (both of which are taxed). If the company buys him his car then it's a taxable benefit too. If the company increases the value of the CEOs shares by doing share buybacks, then the CEO just pays more capital gains taxes. Avoiding corporation tax means the tax paid directly by the company goes down, but it's not at all obvious that the net amount the government receives goes down. Only direct taxes are reflected on their balance sheet, though, which is a good enough incentive.