Best judgment assessment allows tax authorities to assess fringe benefits when employers default on returns or notices. Best judgment assessment empowers the Assessing Officer to assess and determine tax payable on fringe benefits when an employer fails to file required returns, fails to file alternative or revised returns, or fails to comply with notices or directions; the AO must consider all relevant material and, after serving a notice to show cause and providing an opportunity of being heard, make the assessment, except where a prior notice under the return-notice provisions was already issued.