** U.S. banks' earnings spark mixed reactions, as scrutiny of the sector deepens due to worries over credit stress

** Shares of Truist Financial TFC.N and Regions Financial RF.N climb 3.8% and 1.3% in premarket trading, respectively, after reporting higher profit in Q3

** Fifth Third Bancorp FITB.O gains 2.8% after a jump in quarterly profit

** However, Bank OZK OZK.O slides 6.4% after falling short of Q3 profit estimates, while Pennsylvania-based FNB FNB.N drops 4% on slower loan growth

** The banking industry, mainly regional lenders that are a lifeline for U.S. small business credit, is back in focus as credit fears mount

** Worries about exposure to the recent bankruptcies at auto parts maker First Brands and subprime lender Tricolor have rattled confidence

** The S&P 500 banks index .SPXBK and the KBW regional banking index .KRX 3% and 6.3%, respectively, on Thursday

(Reporting by Niket Nishant in Bengaluru)

((Niket.Nishant@thomsonreuters.com))