蒙特利尔银行美股招股说明书(2025-12-08版)

The information in this preliminary pricing supplement is not complete and may be changed. This preliminary pricing supplement and the accompanying productsupplement, underlying supplement, prospectus supplement and prospectus are not an offer to sell these securities and we are not soliciting an offer to buy thesesecurities in any jurisdiction where the offer or sale is not permitted. Subject To Completion, dated December 8, 2025PRICING SUPPLEMENT dated December , 2025 (To Product Supplement No. WF1 dated March 25, 2025,Underlying Supplement No. ELN-1 dated March 25, 2025,Prospectus Supplement dated March 25, 2025and Prospectus dated March 25, 2025) Bank of Montreal Senior Medium-Term Notes, Series KEquity Index Linked Securities Market Linked Securities—Auto-Callable with Leveraged Upside Participation and FixedPercentage Buffered Downside Principal at Risk Securities Linked to the Lowest Performing of the Nasdaq-100 Index® 4, 2028 Linked to the lowest performing of the Nasdaq-100 Index®and the S&P 500®Index (each referred to as an “Underlier”)Unlike ordinary debt securities, the securities do not pay interest or repay a fixed amount of principal at maturity and are subject to potential automatic callupon the terms described below. Whether the securities are automatically called for a fixed call premium or, if not automatically called, the maturity paymentamount, will depend, in each case, on the performance of the lowest performing Underlier on the call date or the final calculation day, as applicable. The lowest Automatic Call.If the closing value of the lowest performing Underlier on the call date occurring approximately one year after issuance is greater than orequal to its starting value, the securities will be automatically called for the face amount plus a call premium of at least 10.65% of the face amount (to bedetermined on the pricing date)Maturity Payment Amount.If the securities are not automatically called, you will receive a maturity payment amount that could be greater than, equal to or less than the face amount depending on the ending value of the lowest performing Underlier on the final calculation day as follows:If the ending value of the lowest performing Underlier on the final calculation day is greater than its starting value, you will receive the face amount plus apositive return equal to 150% of the percentage increase in the value of that Underlier from its starting valueIf the ending value of the lowest performing Underlier on the final calculation day is less than its starting value but not by more than the buffer amount of8%, you will receive the face amount If the ending value of the lowest performing Underlier on the final calculation day is less than its starting value by more than the buffer amount, you willreceive less than the face amount and have 1-to-1 downside exposure to the decrease in the value of the lowest performing Underlier on the final Investors may lose up to 92% of the face amountIf the securities are automatically called, the positive return on the securities will be limited to the call premium, and you will not participate in anyappreciation of either Underlier, which may be significant. If the securities are automatically called, you will no longer have the opportunity to participate inany appreciation of either Underlier at the upside participation rate Your return on the securities will depend solely on the performance of the Underlier that is the lowest performing Underlier on the call date or the finalcalculation day, as applicable. You will not benefit in any way from the performance of the better performing Underlier. Therefore, you will be adverselyaffected if either Underlier performs poorly, even if the other Underlier performs favorablyAll payments on the securities are subject to the credit risk of Bank of Montreal, and you will have no ability to pursue any securities included in eitherUnderlier for payment; if Bank of Montreal defaults on its obligations, you could lose some or all of your investmentNo periodic interest payments or dividends No exchange listing; designed to be held to maturity or automatic call The securities are the unsecured obligations of Bank of Montreal, and, accordingly, all payments on the securities are subject to the credit risk of Bank of Montreal.If Bank of Montreal defaults on its obligations, you could lose some or all of your investment. The securities are not insured by the Federal Deposit InsuranceCorporation, the Deposit Insurance Fund, the Canada Deposit Insurance Corporation or any other governmental agency. The securities are not bail-inable notes and are not subject to conversion into our common shares or the common shares of any of our affiliates under subsection39.2(2.3) of the Canada Deposit Insurance Corporation Act.Neither the Securities and Exchange Commission nor any state securities commission or other regulatory body has approved or disapproved of these securities or