Between mid-September and mid-October of 2016, the Securities and Exchange Commission (SEC) put Tesla Inc. under fire after the latter added back certain costs to revenue using non- GAAP earnings. While the use of non-GAAP earnings is allowed to some extent, Tesla violated the US GAAP. In four separate comment letters sent from the SEC to Tesla, the regulatory body inquired about "...a statement disclosing the reason why you believe that the presentation of a non-GAAP financial measure provides useful information to investors..not how your management uses the information". 1. Why the SEC had to issue four comment letters to Tesla? 2. What does non-GAAP earnings mean? Why it is violation of US GAAP in some situations? 3. What are the differences between GAAP and non-GAAP earnings numbers according to Tesla's financial statements during the above period? 4. Briefly summarize the response from Tesla to the SEC and whether it makes sense to you. Please support your answer. 5. What are the efforts made by the SEC subsequent to the infamous Tesla's scenario? Do you think these efforts helped in curbing non-GAAP earnings by other firms and why?