It can be that due to the name change that some charting websites don't show pre-symbol changes, but on sites like these one can still see the trading pattern dating years back!  http://www.vantagewire.ca/company?symbol=PTK%...mp;ticker=

Other websites (of brokers) depict POET Technologies inc; as PTK, V.PTK, PTK.V, POETF, PTK.C, C.PTK, CVE.PTK, CN.PTK, PTK.CN, CA.PTK, PTK.CA, PTK.VN, VN.PTK ...