She also said that while DTCC could place restrictions on clearing and settlement of issues held at its depository, trading could continue at a broker’s discretion if a customer held physical certificates either directly or through a Direct Registration position. “It would be much better if microcap fraud could be stopped before the trade takes place, rather than at the clearance and settlement level,” Nahari stated.
this is from the dtc's website
This may be why your shares are no longer trading, or showing up on the ask. if your broker didnt hold enough physical certificates, they cannot trade. so a portion of your shares may have been held as physical certs and the rest were just on record with dtc. the ones on record with dtc cannot be traded.