1-Audit of historical financial statements :

Managements asserts that the statements are fairly stated in accordance with GAAP ( Generally Accepted Accounting Principles ) , the auditor issues a written report expressing an opinion about whether financial statements are fairly stated in accordance with GAAP .

Publicly held companies are required to have an auditor because there are many external users rely on these statements to make business decisions .

2-Audit of internal control over financial reporting :

Management asserts that internal control has been developed and implemented with following a well established criteria .

The auditor expresses an opinion on effectiveness of internal control because effective internal control reduces likelihood of failure misstatements in financial statements .

3-Review of historical financial statements :

It provides moderate level of assurance on financial statements and less evidence is necessary and it involves less extensive examination .

Many non-public companies prefer review services because it's less costly than an audit .

4-Attestation services on information technology :

As transactions and information are shared online , there is greater demand for assurance about information , transactions and security protecting them .

An example of attestation service is web trust and sys trust ( system trust ) .

Web trust services : symbolic representation of CPAs ( Certified Public Accountant ) report on managements assertions about its disclosure of electronic commerce practice and it's for a third party users like creditors and stockholders .

Sys trust services : test system reliability such as security and data integrity and it's for managements .

written by : Mohamed Mostafa .