Founder and CEO of US online social networking and social networking support Facebook Mark Zuckerberg responds upon his arrival for a meeting with European Commission vice-president accountable for Values and Transparency, in Brussels, on February 17, 2020. (Photo by Kenzo TRIBOUILLARD / AFP) (Photo by KENZO TRIBOUILLARD/AFP through Getty Images)KENZO TRIBOUILLARDShares of Facebook stock closed more than 6% on Thursday after the U.S. launching of Reels, a fresh Instagram attribute built to rival Chinese upstart TikTok. Reels is a short-form movie quality that enables Instagram users to make content using overlaid sound and augmented reality impacts, much as they can on TikTok.The attribute was initially introduced in Brazil in November 2019, however on Wednesday, Instagram introduced the characteristic in the U.S. and other niches as part of its Instagram program. For Facebook, TikTok has grown as a threat because of its rising popularity among U.S. teenagers and young adults. TikTok asserts over 100 million monthly active consumers at the U.S., ” a spokeswoman told CNBC.