Appearing on CNBC, BlackRock (BLK) fixed income chief Rick Rieder confirms his firm's move into Bitcoin (BTC-USD) investment, saying "we've started to dabble in it."Not all dabbles are equal, of course, as BlackRock manages nearly $9T in assets.Rieder, along with BlackRock chief Larry Fink a couple of months ago both indicated an interest in investing in crypto, and filings earlier this year included language about certain of the asset manager's funds investing in that space.Rieder this morning: "My sense is the technology has evolved and regulations have evolved to the point where a number of people feel it should be part of the portfolio."Bitcoin is currently trading at $50.9K after earlier this morning pushing all the way to $51.5K.