Some of you don't quite know how it works.
The ARK 3D Printing ETF is an index fund, which means it is not actively managed, it is an ETF which mimics an index. Cathy Wood has not put HPQ in the ETF because HPQ is not part of the underlying index, which is established by the index creator, in this case Solactive.
Unless HPQ shows up here, it's unlikely it's going to be in the ARK fund. Go here and then look under the "index composition" tab to see the companies:
https://www.solactive.com/Indices/?index=DE000SLA1A36 Also, once the initial position has been established (which it seems to have been by this point), the daily buying of PYR into the ETF has nothing to do with Cathie and ARK liking or disliking a company, it is based on the daily inflow of new money into the ETF by investors. The more it sells, the more money is distributed evenly across the companies within the ETF by the purchase of more shares based on each company's assigned weighting within the ETF.
This weighting changes when 1/ a new position in a company is being established, 2/ during the quarterly rebalancing of the weighting of the fund, and/or 3/ in exceptional circumstances, say when one company in the fund is struggling/delisted/bought out etc, and other company's weighting's are changed to compsenate.