Timing: An issuer with an average trading volume less than $1 million per day or a public float value below $150 million is unable to trade within the last 30 minutes of trading. Companies with higher average-trading-volume or public float value can trade up until the last 10 minutes. Read more: Rule 10b-18 https://www.investopedia.com/terms/r/rule10b18.asp#ixzz57sYVGetb Follow us: Investopedia on Facebook That's from your own link. Doesn't matter though, MYDX cannot legally buy back shares off the market because the company is net negative.