Gainers
$Flotek Industries(FTK.US)$ rose 48.6% to $0.8322 in pre-market trading after the company said it had received an unsolicited takeover offer for part or all of the company.
$Spruce Biosciences(SPRB.US)$ rose 17.34% to $4.94 in pre-market trading after jumping 13% on Monday. Oppenheimer recently initiated coverage on the stock with an Outperform rating and a $15 price target.
$Allied Healthcare Products(AHPI.US)$ rose 10.0% to $6.60 in pre-market trading after gaining around 4% on Monday.
$Addvantage Technologies(AEY.US)$ rose 9.78% to $2.02 in pre-market trading. ADDvantage Technologies reported earnings of $0.05 per share for the fourth quarter, versus a year-ago loss of $0.09 per share.
$Bit Brother(BTB.US)$ rose 6.79% to $0.598 in pre-market trading.
$Kiora Pharmaceuticals(KPRX.US)$ rose 6.56% to $0.95 in pre-market trading. Kiora Pharmaceuticals recently appointed David Hollander, MD, MBA, to its Board of Directors.
$Aurora Mobile(JG.US)$ rose 5.83% to $1.09 in pre-market trading after the company said it has received CAICT's Data Security Governance certification.
Losers
$Powerbridge Technologies(PBTS.US)$ fell 18.3% to $0.76 in pre-market trading after jumping 62% on Monday.
$Microbot Medical(MBOT.US)$ shares fell 9.4% to $8.11 in pre-market trading. Microbot Medical shares jumped 65% on Monday after the company announced a strategic collaboration with Stryker Corporation to develop the LIBERTY robotic system for neurovascular applications.
$Nxt-ID(NXTD.US)$ shares fell 8.47% to $4.32 in pre-market trading after climbing around 18% on Monday.
$American Virtual(AVCT.US)$ fell 6.2% to $2.41 in pre-market trading after jumping 35% on Monday.
$Society Pass(SOPA.US)$ shares fell 6.1% to $13.19 in pre-market trading after dropping 12% on Monday.
$Marathon Digital(MARA.US)$ fell 4.3% to $37.70 in pre-market trading.