I think it could be simply that there is tax-loss selling and no buyers. Who in their right mind would buy warrants executable at $19 when the SP is struggling to go over $4?

I certainly will not buy any, even thought they are tradable because they are hard to trade with the low volume.

I still have 3000 warrants...thankfully sold the rest when the merger announced. I have not written them off as they will appreciate with a significant increase in the AUM share price. There is also a possibility of re-pricing, although I don't count on it. I watch the trading on AUM all day, but rarely even glance at the price of the warrants. I will be pleasantly surprised if I get a decent return on them before the expiration.

On the other hand...if you like to gamble, and you think AUM will get back to the merger price, they are so cheap that some serious money could be made by picking up a few.