When SIND insiders can sell

NYSE under the symbol "SIND." Lock-Up Agreements We and all of our directors and executive officers and the holders of substantially all of our outstanding common stock, stock options and restricted stock units, including Fresnillo, have agreed that, subject to certain exceptions, we and they will not, for a period of 180 days following the date of this prospectus (the " Lock-up Period "), without the prior written consent of Morgan Stanley & Co. LLC, Scotia Capital (USA) Inc. and BMO Capital Markets Corp. on behalf of the underwriters: offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any shares of common stock or any securities convertible into or exercisable or exchangeable for share…

…nt sales of the common stock or other securities acquired in open market transactions); or facilitating the establishment of a trading plan on behalf of a stockholder, officer or director of the Company pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of common stock ( provided that (i) such plan does not provide for the transfer of common stock during the Lock-up Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by or on behalf of the undersigned or the Company regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of common stock may be made under such plan during the Lock-up Period).

The restrictions described in the immediately preceding paragraph do not apply to: transfers as bona fide gift or for bona fide estate planning purposes, by will or intestate succession, or to immediate family members or trusts for their benefit (provided that such transfers do not involve a disposition for value, the transferee agrees to be bound by the lock-up and no filing under Section 16(a) reporting a reduction in beneficial ownership is required or voluntarily made during the Lock-up Period); for any cor…

…or will be a participant; the amount involved exceeded or will exceed $120,000; and any of our directors, executive officers, or beneficial owners of more than 5% of any class of our capital stock, or any members of the immediate family of or any entity affiliated with any such person, had or will have a direct or indirect material interest. Term Loans On May 14, 2024, we entered into the May 2024 Term Loan with ESOF II for an aggregate principal amount of $6.0 million, bearing interest at a rate of 12.00% per annum. On November 1, 2024, we entered into the November 2024 Term Loan with EGH for an aggregate principal amount of $6.0 million, bearing interest at a rate of 12.00% per annum.

" Directed share program At our request, the underwriters have reserved for sale, at the initial public offering price, up to 5% of the common stock offered by this prospectus for sale to our directors, officers, employees, consultants and existing stockholders and other persons having a relationship with us, such as suppliers, or having a relationship with our directors, officers, employees, consultants and existing stockholders.

…mation in this prospectus, including the number of shares that will be outstanding after the completion of this offering and other share-related information, excludes: 11,773,851 shares of common stock issuable upon the exercise of stock options outstanding as of March 31, 2026, at a weighted average exercise price of $2.92 per share; 480,000 shares of common stock issuable upon the settlement of restricted stock units outstanding as of March 31, 2026, all of which will vest upon the completion of this offering and are expected to be issued shortly following the completion of this offering; 776,500 shares of common stock issuable up…