Answer
Ideally, Accounting Principle Board (APB) opinions refers to an authoritative pronouncement that is usually issued by the APB in reaction to various accounting issues that require clarification or rather interpretation. Accounting Standards Updates (ASU)on the other hand are pronouncements made by the Financial Accounting Standards Board (FASB) that re usually made up of codification and along the same lines representing the accounting profession's authoritative pronouncements on financial accounting and reporting practices.
Work Step by Step
Similarly, its important to note that APB was disbanded in the hopes that a smaller independent body FASB will be more effective in creating accounting standards, on the other hand since then ASU has effortlessly tried to explain why FASB decided to change US GAAP as well the background information related to the change.
