Under-reported volume in AAPL cannot advantage one trader over another. I don't disagree, however, that odd-lots can be used by HFTs/algos for price-discovery.

Under-reported volume in AAPL cannot advantage one trader over another. I don't disagree, however, that odd-lots can be used by HFTs/algos for price-discovery. I don't think that this necessarily disadvantages any market participants. Odd lot pings are just ways for HFTs to reduce their capital outlay. You simply don't want to commit too much capital to "ping" passive dark pool orders. So, in the new odd-lot reporting method, oddlot pings will now be reported to the tape. I would argue, however, that this makes no difference to the HFT. The consolidated tape is so slow, that by the time other HFT participants can digest an odd-lot fill from a darkpool, that remainder of the passive dark order would have already been gone/hit/lifted by the pinger. I view this behaviour purely as proper functioning of the markets...