Dive Brief:

• Update: Wall Street staged a rebound Tuesday after global-growth fears struck stocks the day prior, with all three major indeces gaining ground at the opening bell. Meanwhile, ad stocks, mirroring market moves, were modestly higher in early morning trade. 
• U.S. stock markets closed on Monday in deep negative territory after a frenetic trading day that saw stocks shed nearly 1,100 points in the first four minutes of trading before climbing back up by midday, only to close more than 580 down (or 3.5%).
• The ad tech sector was not left unscathed. From TubeMogul and Criteo to Facebook, Twitter, Google, and Netflix, ad-related stocks tumbled early in the day before clawing back. Twitter dropped 16% shortly after the opening bell Monday, while Facebook fell 10%.
• Meanwhile, agency shares – WPP, Omnicon, Publicis, Interpublic – traded modestly lower, seemingly more insulated from the market fluctuations than the ad tech sector. 

Dive Insight:

In a relief rally, Wall Street soared at the opening bell Tuesday following the previous day's global rout. At 10 a.m. ET, Facebook, Twitter and Google were all up 2 to 4%, as were notable agency stocks WPP, Omnicon and Interpublic. Meanwhile, Netflix jumped 6%, TubeMogul was up 8% and Criteo almost 2%.

Global markets felt a jolt after the Chinese stock market plunged in a volatile day of trading Monday. All S&P 500 sectors were hard hit, dropping about 5%. By end of trading, all three major indexes had entered "correction" territory after several tumultous days on the Street, at least partly due to a decline in oil prices and anxiety over the state of the global economy. 

How Monday's selloff will impact marketers is still unclear. Agencies are pulling into the second half of a chaotic year where media reviews are well past the billion-dollar mark. These stocks were largely untouched by the day's whiplash, but the same cannot be said of other media brands. 

A shift to digital is causing headaches for TV companies like Time Warner. Last week, media shares took an added blow after a report said TV advertising was in "undeniably in secular decline." The Wall Street Journal noted that at the end of last week, TV media stocks had already fallen 19% in August and agency shares had been underperforming. That being said, online streaming video service Netflix has fallen 21% over the past three days -- a sign that victims of the sell-off came in all shapes, sizes, and sectors.

More notable than today's sell-off, however, is the fact that many ad tech companies have not grown with the rest of the market over the last year. While the Dow Jones Industrial average grew over 5% from July 2014 to 2015, "some of the better-performing publicly traded ad tech companies had no growth in share value, while others fell off a cliff," according to AdExchanger.