You take $51 to a Las Vegas roulette table and bet it all on black.
50-50 chance there's $102 afterwards and shareholders and employees get to share most of the $51 gain; 50-50 chance there's $0.
Taking outsized risks with other peoples' money is a great gig for both stockholders and executives. We normally prohibit financial services firm from engaging in this kind of behavior, because the economic incentives favor outsized risk.
Even if depositors lose 5%. 5% that they shouldn't have earned because of the ultra high-risk position taken, maybe it's from them it should be taken...
A "money market" account means the money is invested in extremely short term government or corporate bonds. SVB probably wasn't paying that 4.5%, they were just passing through what the market is paying for money market funds right now.