It's usually because you have too many stock transactions.
If you're filing any of these forms:
Form 1098-C, Form 2848, Form 3115, Form 3468, Form 4136, Form 5713, Form 8283, Form 8332, Form 8858, Form 8864, Form 8885, or Form 8949,
Address them to (with Form 8453 as a cover sheet):
Attn: Shipping and Receiving 0254
Receipt and Control Branch
If you're paper filing a 1040, find your state here.
