I know this is an old post, but it still comes up in a general search for W2 information, and the answers here are so completely incorrect, that I have to speak up.
As an actor, SAG-AFTRA is not your employer. Unless you go into an actual SAG-AFTRA union office, sit at a desk, drink their coffee, and answer phones or whatever, you are not a SAG-AFTRA employee. SAG-AFTRA is our union. They are a clearinghouse for residual payments, which is why you get checks in the mail from the Union, with a SAG-AFTRA cover statement with the same info on it as the paystub. Producers and payroll services mail your residuals to the Union, then SAG-AFTRA processes it to make sure the producers paid the appropriate amount into the health and retirement funds as required by the contract. Then the Union sends it to your current address on file. The employer who issues your W2 in January is the production company or payroll company standing in as employer: Entertainment Partners, WB, Disney, etc. If you have all your paystubs still (it's a good idea to keep them to make sure you got all your W2s), they should add up to the total on the W2. Session earnings and maybe original run residuals will come to you or your agent directly. Again, your agent is not your employer in this case. The subsequent residuals will generally go through the union for all the years to come. You will only get one W2 per employer, though perhaps 1099s for Foreign Royalties, which yes, are a pain and add to your tax preparation cost. For a small-earnings actor, processing the 1099 will often cost more than the earnings listed on it. It seems pretty unfair to me.
ALSO, if you get a 1099 for acting work (not just Foreign Royalties), you are considered a local small business and if you're in the City of L.A., you also have to file and annually renew your City Business Tax License. There is no fee/tax if you file on time and don't make much money (I think you have to pay if you make over $100,000 that year...but don't quote me on it.) If you DON'T register and renew, then you owe the taxes and late fees and penalties, regardless of how little you earned as an independent contractor (1099).
Anyway, don't listen to people who tell you that SAG-AFTRA is your employer or owes you a W2. Maybe they can help you find it, if you ask nicely, but it's from the actual employer, not them.
