In the U.S., generally accepted accounting principles, commonly abbreviated as US GAAP or simply GAAP, are accounting rules used to prepare, present, and report financial statements for a wide variety of entities, including publicly-traded and privately-held companies, non-profit organizations, and governments. Generally GAAP includes local applicable Accounting Framework, related accounting law, rules and Accounting Standard. Similar to many other countries practicing under the common law system, the United States government does not directly set accounting standards, in the belief that the private sector has better knowledge and resources. US GAAP is not written in law, although the U.S. Securities and Exchange Commission (SEC) requires that it be followed in financial reporting by publicly-traded companies. Currently, the Financial Accounting Standards Board (FASB) is the highest authority in establishing generally accepted accounting principles for public and private companies, as well as non-profit entities. For local and state governments, GAAP is determined by the Governmental Accounting Standards Board (GASB), which operates under a set of assumptions, principles, and constraints, different from those of standard private-sector GAAP. Financial reporting in federal government entities is regulated by the Federal Accounting Standards Advisory Board (FASAB). The US GAAP provisions differ somewhat from International Financial Reporting Standards (IFRS), though former SEC Chairman Chris Cox set out a timetable for all U.S. companies to drop GAAP by 2016, with the largest companies switching to IFRS as early as 2009 Basic objectives
Financial reporting should provide information that is:
•useful to present to potential investors and creditors and other users in making rational investment, credit, and other financial decisions. •helpful to present to potential investors and creditors and other users in assessing the amounts, timing, and uncertainty of prospective cash receipts. •about economic resources, the claims to those resources, and the changes in them.  Basic concepts
To achieve basic objectives and implement fundamental qualities GAAP has four basic assumptions, four basic principles, and four basic constraints.  Assumptions
•Accounting Entity: assumes that the business is separate from its owners or other businesses. Revenue and expense should be kept separate from personal expenses. •Going Concern: assumes that the business will be in operation indefinitely. This validates the methods of asset capitalization, depreciation, and amortization. Only when liquidation is certain this assumption is not applicable. •Monetary Unit principle: assumes a stable currency is going to be the unit of record. The FASB accepts the nominal value of the US Dollar as the monetary unit of record unadjusted for inflation. •The Time-period principle implies that the economic activities of an enterprise can be divided into artificial time periods.  Principles
•Cost principle requires companies to account and report based on acquisition costs rather than fair market value for most assets and liabilities. This principle provides information that is reliable (removing opportunity to provide subjective and potentially biased market values), but not very relevant. Thus there is a trend to use fair values. Most debts and securities are now reported at market values. •Revenue principle requires companies to record when revenue is (1) realized or realizable and (2) earned, not when cash is received. This way of accounting is called accrual basis accounting. •Matching principle. Expenses have to be matched with revenues as long as it is reasonable to do so. Expenses are recognized not when the work is performed, or when a product is produced, but when the work or the product actually makes its contribution to revenue. Only if no connection with...