I concur with Karl Stevens in fact most S Corporations today are LLC's at the legal entity level. S Corp and LLC are two very different questions. As to the original question about making an 83(b) election, it is very critical that you understand the consequences of making the election for restricted stock in an S Corp, but if you should or should not make the election will depend on the specific circumstances and both the tax impact on the person receiving the grants and the current S Corp shareholders.If you receive a stock grant for an S Corp and make an 83(b) election then you are considered as being an owner of the S Corp. That means you are required to be allocated a proportionate share of the income of the S Corp each year based on your ownership percentage and if the current shareholders receive a distribution of cash, you have to also receive a proportionate distribution.You also have to take into consideration that making an 83(b) election means the grant recipients by being considered shareholders could terminate the S election if any one of them is a ineligible S Corp shareholder or if adding shareholders puts the number of shareholders over 100.If you do not make the election, then you are not considered a shareholder and thus cannot receive distributions from the corporation and the corporation may be required to accrue any shareholder benefits that would otherwise be due to you during the vesting period.Finally the company needs to be very sure that nothing in the vesting and grant agreements creates a second class of stock that would terminate the S election.You will not know how "important" the 83(b) election is until after it is too late to do anything about it. You have 30 days from the date you receive the grant to make the 83(b) election, but all the election does is accelerate you recognizing income for the receipt of restricted stock, that you would otherwise not have to report as taxable income. You do this because if you recognize the value of the stock today as ordinary income, then years from now when you sell the stock you get capital gain treatment on the appreciation in value between today and that future date. If there was a substantial increase in value in the future, then making the 83(b) election was very important and will greatly reduce your tax burden. If instead the value of stock decreases or becomes worthless, then you made the wrong choice as you would have been better off to have not filed the election.You will often hear people say "you should always file an 83(b) when you receive restricted stock". That statement is based on the fact that no reasonable person would take payment for work done in the form of stock that they can't sell today, unless they believed that the stock was going to be worth a lot more in the future when they can sell it. Add to that the fact that the resulting tax liability when you do sell the stock can be 1/2 of what it would be if you did not make the 83(b) election and you get that filing the election is the safe choice. However, the failure rate of startup companies would tell you that making an 83(b) election is probably the wrong decision just as often as it is the right decision.