Their intervention in Yemen doesn't seem to go all too well but perhaps more surprising has been the drop in their global assets. 50+ billion is only part of their holdings but it shows they have a huge deficit to cover:

With income from oil accounting for about 80 percent of revenue, Saudi Arabia’s budget deficit may widen to 20 percent of gross domestic product this year, according to the International Monetary Fund. SAMA plans to raise between 90 billion riyals ($24 billion) and 100 billion riyals in bonds before the end of the year as it seeks to diversify its $752 billion economy, people familiar with the matter said in August.
Diversification has been buzzing around for decades, if I'm not mistakes. Funny how the Saudi manager of the pv plants is making exactly the same point as we did some years ago in the energy security thread. Cut the stupid fuel subsidies, save money and sell more abroad to get much more money. Then again this is basic math and common sense so it wasn't all that difficult to get right. In any case the public addiction to those state-sponsored prices will be hard to crack.