Bitcoin is back. The digital currency—which, unlike the cash in your wallet, is not issued by a central bank—has surged this year on bitcoin exchanges, hitting a new high today above $31.

Bitcoin hasn’t traded at this level since June 2011, which is an ominous observation since that peak was followed by the currency’s collapse, precipitated by an enormous sell order from a hacked account. But it recovered throughout 2012 and has begun to seem more more like a legitimate alternative to currencies issued by sovereign nations. Traders at large investment banks, including Morgan Stanley and Goldman Sachs, are said to be active on bitcoin exchanges.