Fake
There are no such half billion dollar securities
They might have been taken to Switzerland to try and use as collateral on a trading account
Pure speculation, but maybe North Korea is involved?
They both try and counterfeit US money, and through selling drugs, etc.,. must reap in huge sums.
With the succession in N. Korea in doubt, and with war a possibility, any number of individuals in the ruling circles there might want to hedge their best and move their loot.
I have never seen a physical long bond, only the short ones. I know that the short bonds only come in denominations as high as $1 million.
But, when countries like China hold almost a trillion dollars, and Japan well over a half trillion dollars in long bonds, is it not possible that there's denominations greater than $1 million?
It seems very far-fetched to me as well, but who knows.