Specialized Disclosure Report (Form SD)

STEM, INC.

CONFLICT MINERALS REPORT

FOR THE FISCAL YEAR ENDED DECEMBER 31, 2025

This Conflict Minerals Report (the "Report") of Stem, Inc. (the "Company," "Stem," "we" or "our") has been prepared pursuant to Rule 13p-1 and Form SD (the "Rule") promulgated under the Securities Exchange Act of 1934, as amended, for the reporting period from January 1, 2025 to December 31, 2025. The Rule requires disclosure of certain information when a company's products include specified minerals that are necessary to the functionality or production of those products. The specified minerals are columbite-tantalite (coltan), cassiterite, gold and wolframite, including their derivatives, which are limited to tantalum, tin and tungsten ("conflict minerals").

The information presented in this Report includes the activities of our majority-owned subsidiaries.

Company Overview; Covered Products

Stem is reimagining technology to drive the energy transition. We help asset owners, operators and stakeholders benefit from the full value of their energy portfolio by enabling the intelligent development, deployment and operation of clean energy assets. Our integrated software suite, PowerTrackTM, provides asset monitoring software and solutions, supported by professional and managed services, under one consolidated set of solutions. Our solutions and services are designed to provide customers with the information they need clearly and accurately and help harness raw data to inform actionable insight. PowerTrack is our integrated suite of software and solutions for solar, storage and hybrid assets. Within the PowerTrack product suite we offer PowerTrack Software, PowerTrack Energy Management System, PowerTrack Supervisory Control and Data Acquisition ("SCADA"), PowerTrack Power Plant Controller ("PPC"), PowerTrack Logger, and PowerTrack Optimizer.

Our PowerTrack Software for solar monitoring and analytics enables the standardization of energy portfolios on one hardware agnostic application. We offer commercial and industrial- and utility-scale edge hardware solutions, which are original equipment manufacturer-agnostic devices that are used to connect customers' solar and storage assets to our software applications in a unified view. We offer project services to our PowerTrack customers to assist with designing and commissioning of solutions. We offer Managed Services, which are full lifecycle, storage services covering the design, procurement, commissioning, operation and optimization of energy storage and hybrid systems, enabled by our PowerTrack Optimizer software, to our customers. We also offer a comprehensive suite of Professional Services to support solar and storage projects through every stage of the project lifecycle, providing our customers with the expertise needed to navigate the complexity and scale of clean energy portfolios. We serve project developers, asset owners, engineering, procurement and construction firms ("EPCs") and distributors. . In some cases, we also resell battery original equipment manufacturer hardware to our customers for a fee.

Because we do not manufacture products that contain conflict minerals necessary to the functionality or production of those products, this Report relates solely to products manufactured by some of our suppliers, containing conflict minerals necessary to product functionality or production ("necessary conflict minerals") (the "covered products").

For the reporting period covered by this Report, our covered products included, edge hardware for solar assets management, energy storage systems comprised of lithium-ion battery modules, converters and related equipment that we source from suppliers and pass along to our customers at project sites.

Reasonable Country of Origin Inquiry

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We engaged Source Intelligence ("SI") as an outside agent to assist and guide us in our Reasonable Country of Origin Inquiry ("RCOI") and due diligence efforts. We then performed an analysis of our supply chain and defined the scope of our RCOI by identifying and contacting suppliers that provided products that we believed were likely to constitute covered products for the reporting period. During our review, we asked scoping questions that allowed us to exclude certain suppliers and ultimately identify 35 suppliers that were within the scope of the Rule.

Because we are several tiers removed from the mining, smelting, or refining of necessary conflict minerals, we then worked with SI to conduct a survey of suppliers using the Conflict Minerals Reporting Template ("CMRT") developed by the Responsible Minerals Initiative ("RMI"). The CMRT is a standardized reporting template that was developed to facilitate disclosure and communication of information regarding mineral country of origin, and the smelters and refiners being utilized in a company's supply chain. The CMRT has been widely adopted and used by many companies in their due diligence processes related to conflict minerals.

We worked with SI to engage with our suppliers and to provide them instructions about the CMRT and its requirements, as well as correct data collection processes for the information provided to us. At various points during the outreach program, the responses were reviewed against criteria developed to help validate such information and determine which suppliers required further engagement. We inquired about responses that were not clear to us and followed up with supplier contacts that were not responsive. We reached out to our suppliers using contacts we believed to be current and up to date. Where one contact person was unresponsive, we reached out to additional known contacts at the relevant supplier. We continued to seek responses through May 18, 2026.

We received a valid CMRT from 29 of the 35 suppliers that we surveyed. The result is a 83% response rate, which is an improvement from our previous year's reporting cycle. Because the CMRTs indicated that some smelters or refiners in the suppliers' supply chains might be sourcing conflict minerals from the Democratic Republic of Congo or an adjoining country (the "covered countries"), we performed additional due diligence, as outlined below.

Due Diligence Program

Program Objectives

We are committed to responsible sourcing, transparency and sustainability in our supply chain. As we learn and gain further operational knowledge as a public company, we will continue to improve our formal processes, strategies and policies to realize these commitments. Our objectives include:

a.Expecting our suppliers to:

i.provide us with timely, accurate and complete information about conflict mineral content and country of origin information on the products supplied to us;

ii.work with us in any review of their supply chain and procurement process, conflict mineral audits, and due diligence on their suppliers as required for our annual SEC disclosure; and

iii.cooperate with us in developing a chain of custody for conflict minerals in the supply chain and identifying and sourcing conflict-free sources for the minerals used in our covered products.

b.Developing and implementing policies and processes toward preventing the use of necessary conflict minerals that may finance or benefit armed groups in the covered countries.

c.Expecting suppliers to actively engage with us on other supply chain due diligence efforts, such as human rights and forced labor assessments.

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We believe in establishing and maintaining long-term relationships with suppliers whenever possible, and we are committed to working closely with our suppliers to accomplish the above objectives.

Diligence Process Design

Our due diligence processes have been designed in conformity with, in all material respects, the Organisation for Economic Co-operation and Development ("OECD") Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas (Third Edition) and the related supplements for gold, tin, tantalum and tungsten (the "OECD Guidance"), consistent with our position in the supply chain for the covered products. The OECD Guidance provides a detailed due diligence framework to support responsible global supply chain management of conflict minerals and other mineral resources and is currently the leading international framework for raw material due diligence. Our process aligns with the following five steps:

a.Step 1. Establish Strong Company Management Systems

b.Step 2. Identify and Assess Risks in the Supply Chain

c.Step 3. Design and Implement a Strategy to Respond to Identified Risks

d.Step 4. Carry Out Independent Third-Party Audit of Smelter/Refiner's Due Diligence Practices

e.Step 5. Report Annually on Supply Chain Due Diligence

As a purchaser of our covered products, we are many steps removed from the mining of conflict minerals. We do not purchase raw ore or unrefined conflict minerals, do not purchase minerals directly from smelters or refiners, and do not conduct purchasing activities directly in any of the covered countries. As we do not have a direct relationship with conflict minerals smelters and refiners, we partnered with SI to help us use conflict mineral reporting resources developed by RMI to disclose upstream actors in the supply chain, and we use the CMRT to gather information on the chain of custody of the conflict minerals included in our covered products.

Due to the breadth, complexity and constant evolution of the global supply chain for the covered products, it can be challenging to verify the origin of all conflict minerals. In addition, the information provided by suppliers may be inaccurate, incomplete or subject to other irregularities. By using our supply chain due diligence processes, driving accountability within the supply chain by leveraging tools and resources developed by RMI and others to validate smelters or refiners as conflict free, and continuing our outreach efforts, we hope to further develop transparency into our supply chain as we grow.

Step 1. Establish Strong Company Management Systems

We have established a cross-functional team that is responsible for complying with the Rule and furthering the other objectives described above. Our team is led by senior leaders from our legal and supply chain departments.

Step 2. Identify and Assess Risks in the Supply Chain

To identify conflict minerals risks in the supply chain for our covered products, we partnered with SI to perform the RCOI, as described above. SI then worked with our cross-functional team to review the CMRT information received from our suppliers during our RCOI. For responses indicating that a smelter or refiner might be sourcing conflict minerals from the covered countries, SI performed an additional investigation to collect information about the source and chain of custody of the conflict minerals. SI also performed additional diligence where responses indicated that a smelter or refiner did not know the origin of the conflict minerals that they sourced.

SI relies on the following internationally accepted audit standards to research smelters and refiners: the Responsible Minerals Assurance Process (RMAP), the London Bullion Market Association Good Delivery Program and the Responsible Jewellery Council Chain-of-Custody Certification. SI is an official vendor member of the RMI

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to further facilitate the exchange of supply chain data and technical information in the quest for global ethical sourcing of materials.

If the smelter or refiner is not certified by these internationally recognized schemes, SI attempts to contact the smelter or refiner to gain more information. Additional research is also performed to determine whether there are any outside sources of information regarding the smelter or refiner's sourcing practices.

Step 3. Design and Implement a Strategy to Respond to Identified Risks

As the completeness and accuracy of the due diligence information improves, our cross-functional team intends to continue to develop strategies to respond to risks in our supply chain. This includes taking steps to support the use of validation, certification and audit programs for smelters and refiners in the supply chain for our covered products. Where a supplier (i) has been unresponsive or otherwise uncooperative in our due diligence efforts or (ii) is not willing to expect its own suppliers to use conflict-free sources, then we may reassess the supplier relationship.

Step 4. Carry Out Independent Third-Party Audit of Smelter/Refiner's Due Diligence Practices

As stated above, we do not have direct relationships with smelters and refiners. As such, we do not perform direct audits of the entities that provide the necessary conflict minerals in our covered products. However, we support and rely on audits of smelters and refiners conducted by third parties, and this information is used throughout our due diligence process.

Step 5. Report Annually on Supply Chain Due Diligence

This Report and our Form SD will be filed with the SEC, and will be publicly available on the investor relations page of our website at investors.stem.com.

Due Diligence Results

Survey Response

We received 29 completed CMRTs from the 35 in-scope suppliers surveyed (an 83% completion rate).

Efforts to Determine Country of Origin of Conflict Minerals

Our efforts to determine the mine or location of origin of the necessary conflict minerals in our covered products with the greatest specificity reasonably possible to us consisted of the due diligence measures described in this Report.

Smelters or Refiners Identified

In total, 365 known smelters and refiners were identified as potentially in the supply chain for our covered products. 10 of the smelters and refiners were identified as having sourced conflict minerals from the covered countries and are not certified by any known organization, and 147 were identified as having no known country of origin for a portion of their conflict minerals.

Set forth in Annex 1 is the list as of May 18, 2026 of all known smelters and refiners identified as potentially being in the supply chain for our covered products. The information provided in Annex 1 is based on information provided by our suppliers and the RMAP. Our suppliers provided responses on a company-wide basis,

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rather than a product basis. As a result, the conflict minerals from the smelters or refiners identified in Annex 1 are not necessarily included in our covered products.

We determined that a portion of the conflict minerals contained in the covered products may have originated from the covered countries, but we were unable to determine the origin of all conflict minerals in our covered products. Therefore, we are unable to conclusively determine the country of origin of the necessary conflict minerals in all our covered products.

Future Process Improvements

We intend to continue to communicate our expectations and information requirements to our direct suppliers and continue to work towards a more transparent and ethical supply chain. In addition, we intend to continue to make inquiries of our suppliers (including, in particular, those suppliers who reported the existence of smelters or refiners that we identified as having sourced conflict minerals from the covered countries and are not certified by any known organization) and undertake additional risk assessments. We expect our direct suppliers to take similar measures with their suppliers so that there is alignment throughout our supply chain.