Item 1.01. Entry into a Material Definitive Agreement.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information provided under Item 1.01 of this Current Report on Form8-Kunder the subheader “ Revolving Credit Facility Amendment” is incorporated into this Item 2.03 by reference.

Item 8.01. Other Events. Also, on October 6, 2025, the Company provided certain updated disclosures, as set forth below. *** Solaris Power Solutions Turbine Expansion Opportunity We have identified an opportunity to purchase approximately 80 MW of immediately available turbine capacity new from a manufacturer that, when combined with our currently available on-ordercapacity scheduled for delivery in the second half of 2026, will increase available turbine capacity to approximately 500 MW. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. SOLARIS ENERGY INFRASTRUCTURE, INC. By: /s/ Kyle S. Ramachandran Name: Kyle S. Ramachandran Title: President and Chief Financial Officer