Organization and Description of Business	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business System1, Inc. and subsidiaries (the "Company", "we", "our" or "us") operates flagship internet utilities including CouponFollow, MapQuest, and Startpage.com, and a best-in-class marketing platform powered by artificial intelligence, enabling third party publishers ("Network Partners") to monetize and maximize the value of user traffic across a wide range of advertising category verticals. On August 1, 2024, we undertook a corporate reorganization, the result of which was that all of the assets and business operations of the Company are now held by System1 Holdings, LLC ("System1 Holdings"), a newly formed intermediate holding company of which we maintain the controlling interest and in which the non-controlling interest is owned by the holders of our Class C common stock. Following the corporate reorganization, (a) System1 Holdings now owns 100% of S1 Holdco, LLC ("S1 Holdco"), the previous intermediate holding company with the non-controlling interests, and 100% of S1 Media, LLC ("S1 Media"), another new subsidiary formed in connection with the corporate reorganization, (b) S1 Media holds the assets and business operations associated with our Products businesses, which include CouponFollow, Startpage and MapQuest, and our acquisition marketing platform and (c) S1 Holdco holds our assets related to our Marketing businesses. System1 Holdings holds our remaining assets and business operations. S1 Holdco and its subsidiaries remain obligors and guarantors under our Term Loan and Revolving Facility, and System1 Holdings and S1 Media are not parties thereto. Liquidity and Going Concern We have evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the condensed consolidated financial statements are issued. We have experienced declining cash flows and financial performance primarily as a result of reductions in Advertising Partners and overall consumer demand for our marketing services. As of March 31, 2026, we had cash and cash equivalents of $51.5 million and negative net working capital, which we define as current assets less current liabilities, of $14.1 million. We had an aggregate principal amount outstanding of $50.0 million under our revolving facility (as defined in Note 5, Debt, Net) with a maturity date of January 27, 2027, and $252.6 million of term debt outstanding on our term loan which matures in July 2027. Management determined, as a result of this evaluation, that our current cash and cash equivalents, net working capital position, and the upcoming maturity date of our revolving facility raise substantial doubt about our ability to continue as a going concern for the twelve-month period following the date of this filing. Our plan is to continue exploring options of refinancing all of our debt obligations. Management cannot conclude as of the date of this filing that its plans are probable of being successfully implemented. There can be no assurance that we will be able to obtain financing that will provide us with sufficient liquidity to satisfy our revolving facility in January 2027 or our term loan in July 2027. As a result, management has concluded that substantial doubt exists about our ability to continue as a going concern. Our condensed consolidated financial statements have been prepared on a basis that assumes we will continue as a going concern which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Accordingly, the accompanying condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.

System1, Inc. and subsidiaries (the "Company", "we", "our" or "us") operates flagship internet utilities including CouponFollow, MapQuest, and Startpage.com, and a best-in-class marketing platform powered by artificial intelligence, enabling third party publishers ("Network Partners") to monetize and maximize the value of user traffic across a wide range of advertising category verticals.

On August 1, 2024, we undertook a corporate reorganization, the result of which was that all of the assets and business operations of the Company are now held by System1 Holdings, LLC ("System1 Holdings"), a newly formed intermediate holding company of which we maintain the controlling interest and in which the non-controlling interest is owned by the holders of our Class C common stock. Following the corporate reorganization, (a) System1 Holdings now owns 100% of S1 Holdco, LLC ("S1 Holdco"), the previous intermediate holding company with the non-controlling interests, and 100% of S1 Media, LLC ("S1 Media"), another new subsidiary formed in connection with the corporate reorganization, (b) S1 Media holds the assets and business operations associated with our Products businesses, which include CouponFollow, Startpage and MapQuest, and our acquisition marketing platform and (c) S1 Holdco holds our assets related to our Marketing businesses. System1 Holdings holds our remaining assets and business operations. S1 Holdco and its subsidiaries remain obligors and guarantors under our Term Loan and Revolving Facility, and System1 Holdings and S1 Media are not parties thereto.

We have evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the condensed consolidated financial statements are issued.

We have experienced declining cash flows and financial performance primarily as a result of reductions in Advertising Partners and overall consumer demand for our marketing services. As of March 31, 2026, we had cash and cash equivalents of $51.5 million and negative net working capital, which we define as current assets less current liabilities, of $14.1 million. We had an aggregate principal amount outstanding of $50.0 million under our revolving facility (as defined in Note 5, Debt, Net) with a maturity date of January 27, 2027, and $252.6 million of term debt outstanding on our term loan which matures in July 2027. Management determined, as a result of this evaluation, that our current cash and cash equivalents, net working capital position, and the upcoming maturity date of our revolving facility raise substantial doubt about our ability to continue as a going concern for the twelve-month period following the date of this filing.

Our plan is to continue exploring options of refinancing all of our debt obligations. Management cannot conclude as of the date of this filing that its plans are probable of being successfully implemented. There can be no assurance that we will be able to obtain financing that will provide us with sufficient liquidity to satisfy our revolving facility in January 2027 or our term loan in July 2027. As a result, management has concluded that substantial doubt exists about our ability to continue as a going concern.

Our condensed consolidated financial statements have been prepared on a basis that assumes we will continue as a going concern which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Accordingly, the accompanying condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.