Blocktonite started keeping track of companies that were meaningfully engaged with blockchain in the summer of 2016. By 4/3/17 we were up to 391 companies. As of 1/15/2018, that number is 770.
Some of these are huge multinationals (IBM, Microsoft, SAP, large banks like BNP Paribas), some are consulting companies, some are law firms – but most are start-ups.