Final answer:
The FASB issues three types of pronouncements: Accounting Standards Updates, Financial Accounting Concepts, and Emerging Issues Task Force Abstracts, which serve to amend codification, provide theoretical frameworks, and offer timely guidance on short-term issues, respectively.
Step-by-step explanation:
The Financial Accounting Standards Board (FASB) issues three major types of pronouncements: Accounting Standards Updates (ASUs), Financial Accounting Concepts (FACs), and Emerging Issues Task Force (EITF) Abstracts. ASUs are used to amend the Accounting Standards Codification, which is the source of authoritative accounting standards. FACs provide the underlying theoretical framework for accounting standards, but are not authoritative themselves. EITF Abstracts result from short-term issues that require timely guidance and are eventually incorporated into the ASUs.