Saudi Arabia ran a record deficit of $98bn last year (~16% of GDP). That's massive and oil wasn't so cheap the whole year so 2016 could be really massive. The government and citizens of Saudi Arabia have a lot less wealth because of the oil price downturn.

To pay for it they are slashing spending and liquidating non-oil assets. Their foreign reserves have gone down over $100bn from their peak and is down to four years at current spending levels. Who wins? Whoever was buying their oil.

Yes, I understand that consumers benefit massively. But they are selling the oil at a lesser profit, not selling it at a loss.

If there was an extrinsic way to say that the value of oil in that ground is higher than the price they are charging for it, then it would clearly be a wealth transfer. Short of that, I don't think it is so clear, it can just be sensible trade.

A dumb insulting analogy: I build you a dresser (pump oil) and use the money you give me to pay for part of a car (I spend the proceeds locally, but also spend more than the proceeds).

If the price for the dresser is fair, I'm obviously not transferring wealth to you.

Even if they are not technically selling at a loss (I actually suspect that they are, but in any case), their opportunity for a particularly high profit margin is something that is priced in to their outlook when they are looking to invest and purchase assets. If all of a sudden they don't have as many marbles to play with, they either need to liquidate assets they currently have to the control of foreign owners and invest more strategically (greater chance of using these marbles in non-wealth creating opportunities) or don't invest at all and lose all of these opportunities in the future.

I can transfer my wealth to you either by just giving it to you, or I can transfer my wealth to you slowly over time by not being able to invest in wealth generation at the same rate as you while my base investments depreciate.