The Globe and Mail reports in its Wednesday edition that bitcoin celebrated its 15th birthday this month by bursting onto Wall Street with an ebullient bang. A Reuters dispatch to The Globe says that now the adolescent asset may have to grow up fast. Investors have embraced 11 U.S. exchange-traded funds (ETFs), tracking bitcoin's spot price, that began trading on Jan. 11 after receiving regulatory approval; after two trading days, they held a total of 644,860 bitcoin worth more than $27-billion (all figures U.S.). Much of that -- more than 500,000 bitcoin -- was already held in a Grayscale Bitcoin Trust that had previously been a closed-end fund before it was allowed to relaunch as one of the new ETFs. The 11 ETFs have seen total inflows of $4.1-billion since Jan. 11. The entrance of the world's largest cryptocurrency into the world's largest stock market "marks the end of the beginning of bitcoin's maturation and growing-up phase," analytics company Glassnode said. Yet it is far too soon to gauge whether the new bitcoin investment products will be able to retain investor interest over the long run, market participants cautioned. Reuters notes that in its latest drama, bitcoin has leapt 50 per cent since mid-October.