The list of former citizens and long term residents is here. The total is 460 for the first quarter of 2012.
The list is discussed on the Isaac Brock site, including some omissions.
I think the explanation for the omissions is in the careful wording at the top of the list:
This notice is provided in accordance with IRC section 6039G of the Health Insurance Portability and Accountability Act (HIPPA) of 1996, as amended. This listing contains the name of each individual losing United States citizenship (within the meaning of section 877(a) or 877A) with respect to whom the Secretary received information during the quarter ending March 31, 2012. For purposes of this listing, long-term residents, as defined in section 877(e)(2), are treated as if they were citizens of the United States who lost citizenship.
The emphasized text tells it all. This is the list people that the Secretary (of the Treasury) heard about in January, February, and March of 2012. It is not the list of people who actually terminated their citizenship or green cards in the first quarter.
I happen to know several people who pulled the plug in Q1 of 2012. They are our clients. They won’t file their final tax returns–with Form 8854 attached–until sometime in 2013. Filing tax returns is the way you notify the Secretary of the Treasury of anything tax-related.
So even though our clients are former citizens at this time, the much-maligned Treasury Secretary legitimately has no clue about these people. And he won’t know until next year. Therefore they are not on this list.