EFTA01378972

The information in this preliminary pricing supplement is not complete and may be changed. This preliminary pricing supplement is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject to completion dated October 11, 2018 Preliminary Pricing Supplement No. U3337 Filed Pursuant to Rule 424(b)(2) To the Underlying Supplement dated April 19, 2018, Registration Statement No. 333-218604-02 Product Supplement No. I-B dated June 30, 2017, October 11, 2018 Prospectus Supplement dated June 30, 2017 and Prospectus dated June 30, 2017 Financial Products CREDIT SUISSEE Contingent Coupon Callable Yield Notes due October 22, 2020 Linked to the Performance of the Lowest Performing of the S&P 500* Index, the Russell 2000® Index and the Nasdaq-100 Index • The securities do not guarantee any return of principal at maturity and do not provide for the regular payment of interest. • Subject to Early Redemption, if a Coupon Barrier Event has not occurred on any trading day during an Observation Period, we will pay a contingent coupon expected to be $30 (to be determined on the Trade Date) per $1,000 principal amount of securities on the immediately following Contingent Coupon Payment Date. If a Coupon Barrier Event has occurred, no contingent coupon will be paid on the immediately following Contingent Coupon Payment Date. • We may redeem the securities, in whole but not in part, on any Contingent Coupon Payment Date scheduled to occur on or after January 22, 2019 but prior to the Maturity Date. No further payments will be made following an Early Redemption. • Investors should be willing to (i) forgo dividends and the potential to participate in any appreciation of any Underlying and (i) lose some or all of their investment if a Knock-In Event has occurred. • Senior unsecured obligations of Credit Suisse maturing October 22, 2020. Any payment on the securities is subject to our ability to pay our obligations as they become due. • Minimum purchase of $1,000. Minimum denominations of $1,000 and integral multiples of $1,000 in excess thereof. • The offering price for the securities is expected to be determined on or about October 17, 2018 (the "Trade Date"), and the securities are expected to settle on or about October 22, 2018 (the "Settlement Date"). Delivery of the securities in book- entry form only will be made through The Depository Trust Company. • The securities will not be listed on any exchange. Investing in the securities involves a number of risks. See "Selected Risk Considerations" beginning on page 7 of this pricing supplement and "Risk Factors" beginning on page PS-3 of any accompanying product supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities or passed upon the accuracy or the adequacy of this pricing supplement or the accompanying underlying supplement, any product supplement, the prospectus supplement and the prospectus. Any representation to the contrary is a criminal offense. Price to Publico) Underwriting Discounts and Commissions(?) Proceeds to Issuer Per security $SI 000 $ $ —$ Total $ --$ 1) CSSU or any other agent may pay selected broker-dealers and other distributors additional marketing, referral or other fees, commissions or retrocessions of up to 1.50% in connection with the distribution of the securities. In no case will the sum of the ees, commissions or retrocessions exceed 1.50%. 2) We or any agent (one of which may be our affiliate) may pay varying discounts and commissions of up to $15 per $1,000 principal amount of securities. For more detailed information, please see "Supplemental Plan of Distribution (Conflicts of nterest)' in this pricing supplement. Credit Suisse Securities (USA) LLC ("CSSU") is our affiliate. For more information, see 'Supplemental Plan of Distribution Conflicts of Interest)" in this pricing supplement. Credit Suisse currently estimates the value of each $1,000 principal amount of the securities on the Trade Date will be between $960 and $990 (as determined by reference to our pricing models and the rate we are currently paying to borrow funds through issuance of the securities (our "internal funding rate")). This range of estimated values reflects terms that are not yet fixed. A single estimated value reflecting final terms will be determined on the Trade Date. See "Selected Risk Considerations" in this pricing supplement. The securities are not deposit liabilities and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency of the United States, Switzerland or any other jurisdiction. Credit Suisse October, 2018 CONFIDENTIAL - PURSUANT TO FED. R. CRIM. P. 6(e) DB-SDNY-0076255 CONFIDENTIAL SDNY_GM_00222439 EFTA01378972