The total amount of investors using margin aka borrowing money to help pay for a trade  is at an all time high of over $1.5 trillion. Is this something we should worry about? We spoke to Jurrien Tinner at Fidelity Investments.  Note: Jurrien Timmer's views are his own and not representative of Fidelity.  Fact checking by Sierra Juarez (npr.org/people/1268825622/sierra-juarez) . Your Next Listen  — How AI might mess with financial markets (lnk.to/zlkvbt) Connect with The Indicator — Sign up for The Indicator’s weekly newsletter (npr.org/indicatornewsletter) ! — Buy the Planet Money book (lnk.to/i3AukBdDWE) — Find our socials, YouTube and more (linktr.ee/indicator_npr) ! — For sponsor-free episodes, subscribe to NPR+ (plus.npr.org) Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org (plus.npr.org) . See pcm.ads...