Apple’s privacy updates are biting into Snap. The Snapchat owner’s shares plunged by more than a fifth in early trading Friday. That cast a shadow over other ad-dependent social media firms that will report earnings results next week, dragging down shares of Facebook, Twitter, and Google’s parent, Alphabet.What upset investors was the photo messaging app owner’s warning Thursday that the impact of Apple’s privacy changes and global supply chain disruptions will linger through the fourth quarter. That’s typically the highest-earning period for social media companies as brands ramp up marketing for the holiday season.Apple’ privacy updates - rolled out over the summer - prevent advertisers from tracking iPhone users without their consent. The tweaks made it hard to measure and manage ad campaigns. As a result, advertisers spent much less than expected.Analysts say Snap will be more impacted by Apple’s changes than other social media giants. The money-losing company earns the vast majority of its revenue from ads on its app.