PRE-FUNDED WARRANTS TO PURCHASE SHARES OF COMMONSTOCK We are offeringof shares of our common stock and, in lieu of the shares of common stock to certain investors that so choose,pre-funded warrants to purchase shares of our common stock. The purchase price of each pre-funded warrant will equal the price per share atwhich shares of our common stock are being sold to the public in this offering, minus $0.0001 per share of common stock, which is theexercise price of each pre-funded warrant. The public offering price for each share of common stock is $. We are also offering theshares of our common stock that are issuable from time to time upon exercise of the pre-funded warrants. Our common stock trades on TheNasdaq Global Select Market (“Nasdaq”) under the symbol “STTK.” On June8, 2026, the last reported sale price for our common stock onNasdaq was $3.90per share. There is no established public trading market for the pre-funded warrants, and we do not expect a market to develop. We do not intend to applyfor listing of the pre-funded warrants on Nasdaq or any securities exchange or nationally recognized trading system. Without an active tradingmarket, the liquidity of the pre-funded warrants will be limited. Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertaintiesdescribed under the heading “Risk Factors” on pageS-6 of this prospectus supplement, and under similar headings inthe documents that are incorporated by reference into this prospectus supplement and the accompanying prospectus. PerSharePerPre-FundedWarrantTotalOffering price$$$Underwriting discounts and commissions(1)$$$Proceeds to us, before expenses$$$ (1)See the section titled “Underwriting” for a description of the compensation payable to the underwriters. Neither the Securities and Exchange Commission nor any state or foreign securities commission or regulatory authorityhas approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplementor the accompanying prospectus. Any representation to the contrary is a criminal offense. The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and theaccompanying prospectus are not an offer to sell and are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is notpermitted.We have granted the underwriters an option for a period of 30 days to purchase up to an additionalshares of our common stock. If theunderwriters exercise the option in full, the total underwriting discounts and commissions payable by us will be $and the totalproceeds to us, before expenses, will be $. Joint Bookrunning Managers Cantor Table of Contents Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSUSE OF PROCEEDSDILUTIONDESCRIPTION OF SECURITIES WE ARE OFFERINGU.S. FEDERAL INCOME TAX CONSIDERATIONSUNDERWRITINGLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE Prospectus ABOUT THIS PROSPECTUSSPECIAL NOTE REGARDING FORWARD LOOKING STATEMENTSTHE COMPANYRISK FACTORSUSE OF PROCEEDSDIVIDEND POLICYSECURITIES WE MAY OFFERDESCRIPTION OF SECURITIES PLAN OF DISTRIBUTION LEGAL MATTERS Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This document is part of the registration statement that we filed with the Securities and Exchange Commission, or the “SEC”, using a ‘‘shelf’’registration process, and consists of two parts. The first part is this prospectus supplement, including the documents incorporated by reference herein,which describes the specific terms of this offering. The second part, the accompanying prospectus, including the documents incorporated by referencetherein, gives more general information, some of which may not apply to this offering. This prospectus supplement relates to the offering of shares ofour common stock and pre-funded warrants. Before buying any of the securities that we are offering, we urge you to carefully read this prospectussupplement, together with the information incorporated by reference as described under the headings “Where You Can Find More Information” and“Incorporation of Certain Information by Reference” in the accompanying prospectus, and any free writing prospectus that we have authorized for use inconnection with this offering. These documents contain important information that you should consider when making your investment decision. Ingeneral, when we refer only to the prospectus, we are referring to both the prospectus supplement and the accompanying prospectus combined. This prospectus supplement describes the terms of securities offered in this offering and also adds to and updates information contained in thedocuments incorporated by reference into this prospectus supplement. To the extent there is a c