{"url_path":"/sec/rntx/10-k/2026/item-12","section_key":"item-12","section_title":"Item 12 Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.","topic":"sec","document":{"doc_type":"10-K/A","doc_date":"2026-04-27","source_url":"https://www.sec.gov/Archives/edgar/data/1420565/0001193125-26-178787-index.html","accession_number":"0001193125-26-178787","cik":"0001420565","ticker":"RNTX","issuer_name":"Rein Therapeutics, Inc.","edgar_url":"https://www.sec.gov/Archives/edgar/data/1420565/0001193125-26-178787-index.html","primary_entity_key":"0001420565","primary_entity_name":"Rein Therapeutics, Inc."},"word_count":1402,"has_tables":true,"body_markdown":"Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.\n\nUnless otherwise provided below, the following table sets forth information regarding beneficial ownership of our shares of common stock as of March 31, 2026, by:\n\n•\neach person, or group of affiliated persons, known to us to be the beneficial owner of 5% or more of the outstanding shares of common stock;\n\n•\neach of our current directors;\n\n•\neach of our NEOs; and\n\n•\nall of our current executive officers and directors as a group.\n\nBeneficial ownership is determined in accordance with the rules and regulations of the SEC and includes voting or investment power with respect to common stock. Percentage of beneficial ownership is based on 28,039,032 shares of common stock outstanding as of March 31, 2026. In addition, shares of common stock subject to options, warrants, or other rights currently exercisable or exercisable within 60 days of March 31, 2026, are deemed outstanding and beneficially owned for the purpose of computing the percentage beneficially owned by (i) the person or entity holding such options, warrants or other rights (but not any other person or entity) and (ii) the directors and executive officers as a group. Except as otherwise noted, the persons and entities in this table have sole voting and investing power with respect to all of the shares of common stock beneficially owned by them, subject to community property laws, where applicable. Except as otherwise set forth below, the address of the beneficial owner is c/o Rein Therapeutics, Inc., 12407 N. Mopac Expy. Suite 250 #390, Austin, Texas 78758.\n\n \n\n \n\nTotal Beneficial Ownership\n\n \n\nName of Beneficial Owner\n\n \n\nNumber of Shares\nBeneficially\nOwned\n\n \n\n \n\nPercentage of\nShares\nBeneficially\nOwned\n\n \n\nNamed Executive Officers and Directors\n\n \n\n \n\n \n\n \n\n \n\n \n\nBrian Windsor, Ph.D.(1).\n\n \n\n \n\n1,057,691\n\n \n\n \n\n \n\n3.6\n\n%\n\nJosef H. von Rickenbach(2)\n\n \n\n \n\n49,850\n\n \n\n \n\n*\n\n \n\nReinhard J. Ambros, Ph.D.(3)\n\n \n\n \n\n52,600\n\n \n\n \n\n*\n\n \n\nWilliam C. Fairey(4)\n\n \n\n \n\n58,195\n\n \n\n \n\n*\n\n \n\nAlan A. Musso(5)\n\n \n\n \n\n58,195\n\n \n\n \n\n*\n\n \n\nTimothy M. Cunningham\n\n \n\n \n\n—\n\n \n\n \n\n*\n\n \n\nDirectors and executive officers, as a group (6 persons)\n\n \n\n \n\n1,276,531\n\n \n\n \n\n \n\n4.4\n\n%\n\n5% + Holders\n\n \n\n \n\n \n\n \n\n \n\n \n\nBios Entities(6)\n      1751 River Run, Suite 400 Fort Worth, Texas 76107\n\n \n\n \n\n1,994,866\n\n \n\n \n\n \n\n7.1\n\n%\n\nVoss Capital, LP\n      3773 Richmond, Suite 850 Houston, Texas 77046\n\n \n\n \n\n4,468,969\n\n \n\n \n\n \n\n15.9\n\n%\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n* Represents beneficial ownership of less than 1% of our outstanding stock.\n\n(1)\nConsists of (i) 2,046 shares of common stock held directly and (ii) 1,055,645 shares of common stock issuable upon the exercise of options within 60 days after March 31, 2026.\n\n(2)\nConsists of 49,850 shares of common stock issuable upon the exercise of options within 60 days after March 31, 2026.\n\n(3)\nConsists of 52,600 shares of common stock issuable upon the exercise of options within 60 days after March 31, 2026.\n\n(4)\nConsists of 58,195 shares of common stock issuable upon the exercise of options within 60 days after March 31, 2026.\n\n16\n\n \n\n(5)\nConsists of 58,195 shares of common stock issuable upon the exercise of options within 60 days after March 31, 2026.\n\n(6)\nBeneficial ownership of the entities affiliated with Bios Partners (the “Bios Entities”) consists of (i) 624 shares of common stock held by Bios Equity Partners, LP; (ii) 110,039 shares of common stock held by Bios Fund I QP, LP; (iii) 188,293 shares of common stock held by Bios Fund I, LP; (iv) 19,274 shares of common stock held by Bios Fund II NT, LP; (v) 143,991 shares of common stock held by Bios Fund II QP, LP; (vi) 44,201 shares of common stock held by Bios Fund II, LP; (vii) 474,105 shares of common stock held by Bios LTI Co-Invest III QP, LP; (viii) 462,731 shares of common stock held by Bios LTI Co-Invest III, LP; (ix) 170,117 shares of common stock held by Bios LTI SPV II, LP; (x) 224,000 shares of common stock held by Bios Clinical Opportunity Fund, LP; (xi) 18,000 shares of common stock held by Bios Fund III NT, LP; (xii) 110,000 shares of common stock held by Bios Fund III QP, LP; (xiii) 17,000 shares of common stock held by Bios Fund III, LP; (xiv) 2,823 shares of common stock and 2,274 shares of common stock issuable upon the exercise of options exercisable as of March 31, 2026 held by Aaron Fletcher; (xv) 644 shares of common stock held by The Aaron Fletcher Trust u/a/d May 17, 2016; (xvi) 644 shares of common stock held by The Holly Fletcher Trust u/a/d May 17, 2016; and (xvii) 6,106 shares of common stock held by The Fucci Family Living Trust u/a/d May 17, 2016. As a result of the blocker provision set forth in the Certificate of Designation of Preferences, Rights and Limitations of the Series X Preferred Stock (the “Certificate of Designation”), the share numbers in the preceding sentence exclude an additional 12,232,000 shares of common stock issuable upon conversion of the Series X preferred stock held in the aggregate by the Bios Entities. The Certificate of Designation provides that any holder of Series X preferred stock will not have a right to convert, subject to certain exceptions, the Series X preferred stock for common stock if, as a result of such conversion, the holder, together with its affiliates and other attribution parties, would hold 19.99% of the total number of shares of common stock then outstanding, subject to decrease upon written notice by the holder. The Bios Entities have provided such notice to decrease the beneficial ownership limitation to 9.99%. The reported share number also excludes additional 1,854,262 shares of common stock issuable upon exercise of warrants held in the aggregate by the Bios Entities, such warrants also being subject to a 9.99% beneficial ownership limitation with respect to the Bios Entities.\n\nSecurities Authorized for Issuance Under Equity Compensation Plans\n\nThe following table contains information about our equity compensation plans as of December 31, 2025. As of December 31, 2025, we had five equity compensation plans, each of which was approved by our stockholders: our 2006 Equity Incentive Plan, as amended (the “2006 Plan”), our 2016 Stock Incentive Plan (the “2016 Plan”), our 2017 Stock Incentive Plan (the “2017 Plan”), our 2021 Stock Incentive Plan (the “2021 Plan”), and our 2017 Employee Stock Purchase Plan (the “2017 ESPP”). The Company also assumed Lung’s 2013 Long-Term Incentive Plan (the “2013 Plan”) as a result of the Lung Acquisition.\n\nEquity Compensation Plan Information\n\n \n\nPlan Category\n\n \n\nNumber of\nsecurities to be\nissued upon\nexercise of\noutstanding\noptions,\nwarrants and\nrights\n\n \n\n \n\n \n\nWeighted\naverage exercise\nprice of\noutstanding\noptions,\nwarrants and\nrights ($/share) (1)\n\n \n\n \n\nNumber of\nsecurities\nremaining\navailable for\nfuture issuance\nunder equity\ncompensation\nplans (excluding\nsecurities\nreflected in\ncolumn (a))\n\n \n\n \n\n \n\n(a)\n\n \n\n \n\n \n\n(b)\n\n \n\n \n\n(c)\n\n \n\n \n\nEquity compensation plans approved by security\n   holders\n\n \n\n3,143,997\n\n \n\n(2)\n\n \n\n \n\n5.21\n\n \n\n \n\n1,921,694\n\n \n\n(3)(4)\n\nEquity compensation plans not approved by security\n   holders(5)\n\n \n\n \n\n—\n\n \n\n \n\n \n\n \n\n—\n\n \n\n \n\n \n\n—\n\n \n\n \n\nTotal\n\n \n\n \n\n3,143,997\n\n \n\n \n\n \n\n \n\n5.21\n\n \n\n \n\n \n\n1,921,694\n\n \n\n \n\n \n\n17\n\n \n\n(1)\nRepresents the weighted average exercise price of the 3,143,997 stock options that were outstanding as of December 31, 2025.\n\n(2)\nConsists of (i) 8,404 shares to be issued upon exercise of outstanding options under our 2016 Plan as of December 31, 2025, (ii) 98,528 shares to be issued upon exercise of outstanding options under our 2017 Plan as of December 31, 2025, (iii) 1,520,179 shares to be issued upon exercise of outstanding options under our 2021 Plan as of December 31, 2025 and (iv) 1,516,886 shares to be issued upon exercise of outstanding options under our Lung’s 2013 Plan as of December 31, 2025.\n\n(3)\nConsists of (i) 1,914,194 shares that remained available for future issuance under our 2021 Plan as of December 31, 2025, and (ii) 7,500 shares that remained available for future issuance under our 2017 ESPP as of December 31, 2025. No shares remained available for future issuance under the 2006 Plan, the 2016 Plan, or the 2017 Plan as of December 31, 2025.\n\n(4)\nOur 2017 ESPP has an evergreen provision that allows for an annual increase in the number of shares available for issuance under the 2017 ESPP to be added on the first day of each fiscal year through the fiscal year ending December 31, 2027, in an amount equal to the least of 31,120 shares of our common stock, 1% of the total number of shares of our common stock outstanding on the first day of the applicable fiscal year and an amount determined by our board of directors. On January 1, 2025 and January 1, 2026, no additional shares were reserved for issuance under the 2017 ESPP pursuant to this provision.\n\n18"}