The FBI holds one of the largest BTC wallets (~600,000 in total) and they can't access it

When the FBI shut down the Silk Road in 2013, an internet black market, it also seized the accused owner’s assets and inadvertently became one of the wealthiest bitcoin operators in the world.

While the FBI may have its hands on the founder of Silk Road’s bitcoin wallet, that doesn’t mean it has access to what's inside. Ross Ulbricht, despite his own self-incriminations as the mastermind behind the online black marketplace, was able to do one thing right: secure his bitcoins.

A reported 600,000 BTC belonging to Ulbricht is in the FBI’s hands. But they can’t access the bitcoin wallet because it is encrypted. This supposedly is separate from the 26,000 BTC that was left in an escrow account, which was being used to exchange money between the marketplace’s users and dealers.

It may make some BTC investors wary that a government entity is in possession of so many bitcoins. After all, it is fear of the Feds trying to shut down decentralized virtual currencies that may be the biggest risk of all right now for considering bitcoin as an asset class.