Nothing prevents it from trading. As today's volume of only 3 shares shows there is hardly any interest in it and millions of shares have been for sale for years and years.
There are hundreds of dead stocks (aka shells) whose tickers are valid that still trade. I even track some of those I follow on a board I created for that purpose and RMTD is one of them.
Eventually, some of them are pulled by Finra and there spirits can finally go to that big private trading platform in the sky.
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