Last month, New York-based ARK Investment Management launchedThe 3D Printing ETF PRNT, the first exchange traded fund dedicated to once-hot 3D printing equities.PRNT follows the 3D-Printing Index. That index is “composed of equity securities and depositary receipts of exchange listed companies from the U.S., non-U.S. developed markets and Taiwan that are engaged in 3D printing related businesses within the following business lines: (i) 3D printing hardware, (ii) computer aided design (“CAD”) and 3D printing simulation software, (iii) 3D printing centers, (iv) scanning and measurement, and (v) 3D printing materials,” according to ARK.