Basis of Presentation and Significant Accounting Policies	9 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	Organization and Business CSP Inc. ("CSPi" or "CSPI" or "the Company" or "we" or "our") was incorporated in 1968 and is based in Lowell, Massachusetts. CSPi and its subsidiaries develop and market IT integration solutions, advanced security products, managed IT services, purpose built network adapters, and high-performance cluster computer systems to meet the diverse requirements of its commercial and defense customers worldwide. The Company operates in two segments, its Technology Solutions (“TS”) segment and High Performance Products (“HPP”) segment. 1. Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying interim condensed consolidated financial statements have been prepared by the Company and reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented. All adjustments were of a normal recurring nature. Certain information and footnote disclosures normally included in the annual consolidated financial statements, which are prepared in accordance with accounting principles generally accepted in the United States, have been omitted. Accordingly, the Company believes that although the disclosures are adequate to make the information presented not misleading, the unaudited condensed consolidated financial statements should be read in conjunction with the notes contained in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2025. The significant accounting policies and estimates used in preparing these Condensed Consolidated Financial Statements were applied on a basis consistent with those reflected in the September 30, 2025 Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended Seeptember 30,2025. Significant Accounting Policies There have been no significant changes to the Company's significant accounting policies described in PART II, Item 8, Note 1 Basis of Presentation and Summary of Significant Accounting Policies, of the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2025. Accounting Pronouncement Not Yet Adopted as of June 30, 2026 In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which provides new optional guidance relating to the estimation of expected credit losses on current accounts receivable and current contract assets under Topic 326. This ASU permits entities to apply a practical expedient when estimating credit losses and is effective for annual reporting periods beginning after December 15, 2025, and interim reporting periods within those annual reporting periods, with early adoption permitted, and should be applied prospectively. We are currently evaluating the adoption of this standard and its impact to the Company's consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income— Expense Disaggregation Disclosures (Subtopic 220-40), which requires expanded disclosures in the notes to the financial statements about certain costs and expenses. This ASU is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, on a retrospective basis. Early adoption is permitted. The Company is currently evaluating the effect of this pronouncement on its disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU expands existing income tax disclosures primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The ASU is effective for all public entities for annual periods beginning after December 15, 2024, with early adoption permitted. Entities should apply the amendments on a prospective basis, but retrospective application is permitted. The Company plans to adopt this ASU on a prospective basis in the fourth quarter of fiscal year 2026. The Company is currently evaluating the impact this ASU will have on its disclosures.

Basis of Presentation and Significant Accounting Policies

9 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation and Significant Accounting Policies

Organization and Business

CSP Inc. ("CSPi" or "CSPI" or "the Company" or "we" or "our") was incorporated in 1968 and is based in Lowell, Massachusetts. CSPi and its subsidiaries develop and market IT integration solutions, advanced security products, managed IT services, purpose built network adapters, and high-performance cluster computer systems to meet the diverse requirements of its commercial and defense customers worldwide. The Company operates in two segments, its Technology Solutions (“TS”) segment and High Performance Products (“HPP”) segment.

1. Basis of Presentation and Significant Accounting Policies

Basis of Presentation

The accompanying interim condensed consolidated financial statements have been prepared by the Company and reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results of the interim periods presented. All adjustments were of a normal recurring nature. Certain information and footnote disclosures normally included in the annual consolidated financial statements, which are prepared in accordance with accounting principles generally accepted in the United States, have been omitted.

Accordingly, the Company believes that although the disclosures are adequate to make the information presented not misleading, the unaudited condensed consolidated financial statements should be read in conjunction with the notes contained in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2025. The significant accounting policies and estimates used in preparing these Condensed Consolidated Financial Statements were applied on a basis consistent with those reflected in the September 30, 2025 Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended Seeptember 30,2025.

Significant Accounting Policies

There have been no significant changes to the Company's significant accounting policies described in PART II, Item 8, Note 1 Basis of Presentation and Summary of Significant Accounting Policies, of the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2025.

Accounting Pronouncement Not Yet Adopted as of June 30, 2026

In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which provides new optional guidance relating to the estimation of expected credit losses on current accounts receivable and current contract assets under Topic 326. This ASU permits entities to apply a practical expedient when estimating credit losses and is effective for annual reporting periods beginning after December 15, 2025, and interim reporting periods within those annual reporting periods, with early adoption permitted, and should be applied prospectively. We are currently evaluating the adoption of this standard and its impact to the Company's consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income— Expense Disaggregation Disclosures (Subtopic 220-40), which requires expanded disclosures in the notes to the financial statements about certain costs and expenses. This ASU is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, on a retrospective basis. Early adoption is permitted. The Company is currently evaluating the effect of this pronouncement on its disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU expands existing income tax disclosures primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The ASU is effective for all public entities for annual

periods beginning after December 15, 2024, with early adoption permitted. Entities should apply the amendments on a prospective basis, but retrospective application is permitted. The Company plans to adopt this ASU on a prospective basis in the fourth quarter of fiscal year 2026. The Company is currently evaluating the impact this ASU will have on its disclosures.