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You will not find a firm that is more responsive
and dedicated to meeting your needs.

Castro & Company has several contract vehicles designed to provide your agency with easy solutions for your contracting needs.


GSA Professional Services Schedule (PSS) 520

Castro & Company holds GSA Professional Services Schedule GS-23F-0038U. This Multiple Award Schedule provides Federal agencies with direct access to professionals that can thoroughly address the needs of the Federal financial community. PSS not only gives agencies access to a multitude of professional financial services, but it also provides agencies with the ability to customize the services to meet their specific needs. The PSS schedule allows for choice, flexibility, ease-of-use, and access to quality firms in the financial arena.

Special Item Number (SIN)

SIN 520-7

Financial & Performance Audits

Perform financial statement audits, financial-related audits, performance audits, and contract audits in accordance with Generally Accepted Government Auditing Standards (GAGAS) and non-GAGAS. An independent assessment of an audited entity’s a) financial statements in conformity with generally accepted accounting principles, b) financial information, adherence to financial compliance requirements and internal controls, or c) organization or program performance to identify areas for improvement.

SIN 520-11


Transaction analysis, transaction processing, data analysis and summarization, technical assistance in devising new or revised accounting policies and procedures, classifying accounting transactions, special studies to improve accounting operations.

SIN 520-8

Complementary Audit Services

Other services performed by auditors including assist in developing questions for use at hearings, develop methods and approaches in evaluating a new or proposed program and forecast potential program outcomes.

SIN 520-13

Complementary Financial
Management Services

Assess and improve financial management systems, financial reporting and analysis, strategic financial planning, financial policy formulation and development. Devise and implement performance measures, conduct special cost studies, perform actuarial services, perform economic and regulatory analysis, assist with financial quality assurance efforts, perform benchmarking.


One Acquisition Solution for Integrated Services (OASIS)

Castro & Company holds One Acquisition Solution for Integrated Services (OASIS). This Small Business Multiple Award Schedule, Indefinite Delivery Indefinite Quantity (IDIQ) contract provides Federal agencies with flexible and innovative solutions for complex services. The core disciplines of the contract include program management, management consulting, logistics, engineering, scientific, and financial services.

This contract:

Spans many areas of expertise and mission spaces
Spans multiple professional service disciplines
Allows flexibility for all contract types, including hybrids and cost-reimbursement, at the task order level
Allows ancillary support components, commonly referred to as Other Direct Costs (ODC), at the task order level

Castro Capabilities for GSA OASIS SB Pool 2

We provide auditing, advisory, and accounting services to the Federal Government including the following specialized areas:

CFO Act and ATDA Financial Statement Audits
Audit Readiness and Remediation
OMB Circular A-123 Internal Control Compliance
Financial Management
Financial Statement Compilations and Analysis
Accounting and Reconciliation Assistance
Audit Liaison Services
Policy and Procedure Development

Primary NAICS Codes:


Offices of Certified Public Accountants


Other Accounting Services

Key Personnel POC Information

Thomas Castro, Managing Partner

Castro’s Corporate OASIS Program Manager (COPM)
Phone: 703-229-4440

Gabriel Fry, Proposal & Contracts Manager

Castro’s Corporate OASIS Contract Manager (COCM)
Phone: 703-229-4440

For general OASIS inquiries,
our OASIS team can be reached at:




Castro & Company is able to receive sole-source contracts, up to a ceiling of $150,000 in accordance with FAR Subpart 19.5-Set-Asides for Small Business.


North American Industry Classification System (NAICS) Codes:

We provide a full range of accounting services including:

541211: Office of Certified Public Accountants
541219: Other Accounting Services
541611: Administrative and General Management Advisory Services
541618: Other Management Advisory Services
541990: Other Scientific and Technical Advisory Services
561110: Office Administrative Services
541519: Other Computer Related Services
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