I have received the form 3921 from my employer.
i had gotten 1000ISO at the certain strike price which i exercised, and sold only 400 of those after exercising on the same year.
My form 3921 has both ( sold + exercise ) stock details, and 1099 has earning details.
I am filing 3921 as AMT, but it will now include sold and exercise stock , but my sold stock is already reported on the 1099 form