The Dow Jones Industrial Index (DJI) is seeing a dramatic rebound off its five-day slump, last seen up 263 points and on track for its best single-session gain since Aug. 5. The S&P 500 Index (SPX) could also snap its losing streak, although the tech-heavy Nasdaq Composite (IXIC) has failed to follow suit and is set for a third-consecutive drop.

A drop in Covid-19 cases and a positive vaccine update from Pfizer (PFE) are helping to bolster sentiment, giving energy and reopening stocks a boost. The Cboe Volatility Index (VIX), meanwhile, is losing steam, puling back from last week's surge toward one-month highs. 

SmileDirectClub Inc (Nasdaq: SDC) is seeing an uptick in bullish options volume, with 77,000 calls across the tape so far, which is four times the intraday average and almost 25 times the number of puts traded. The most popular is the September 6 call, followed by the 5.50 call in the same series, with positions being opened at the latter. SDC was last seen up 9.6% at $5.64, pacing for its highest close in almost two weeks, with newfound support at the 20-day moving average. 

One of the top-performing stocks on the Nasdaq today is Aterian Inc (Nasdaq: ATER). The equity was last seen up 45.2% at $17.14 today, marking its highest level mid-June, and pacing for a close above the 320-day moving average for the first time in two months. ATER has been the target of retail traders of late and is seeing a huge spike in trading volume today, taking its place as one of the most actively traded stocks on the U.S. exchanges this afternoon. ATER has added 206.8% in September alone so far. 

MiMedx Group Inc (Nasdaq: MDXG) is one of the worst-performing stocks on the Nasdaq, last seen off 60.4% at $6.15 after the drugmaker said its top-line results of its Phase 2B clinical trial for its Knee Osteoarthritis (KOA) treatment did not hit its main goal, while its Phase 3 trial of its Plantar Fasciitis (PF) treatment failed to meet its primary endpoint as well. The security hit a four-year high of $15.99 last week on Sept. 9, though today's bear gap has it trading at its lowest level of 2021.