several years:
"the government would likely own these
banks for years. Virtually all American support-
ers of nationalization view it as a temporary receiv-
ership. Unfortunately, the complexity and size of
the largest banks would almost certainly require
major government ownership for many years, ex-
acerbating the concerns about the government be-
ing a worse long-term owner than the private sec-
tor. First, there simply are no acceptable buyers at
the moment with the wherewithal and interest in
buying all or a major part of Citigroup or Bank of
America at a good price. It will likely be some time
before private capital is interested in re-entering the
field in the necessary size. If anyone is lured in be-
fore then, it would almost certainly be as a result of
a truly “fire sale” price. Second, the very complexity
and interconnectedness of the parts of these large
banks would require a long time to sort out, again
unless the government were willing to sacrifice a
great deal of economic value for speed.
It is worth remembering that it took the govern-
ment seven years to completely divest Continental
Illinois, despite the much more benign environ-
ment, including a roaring bull market for much of
the period. Citigroup has 50 times as many assets
and a much more diverse set of operations. Similar-
ly, there was great hope of divesting many of AIG’s
operations quickly, especially as some of them are
strong operations with their own well-respected
brands. To date, however, there has been very little
progress on this score, largely because everyone,
it seems, is trying to divest operations at the same
time. "
http://www.brookings.edu/papers/2009/0225_bank_nationalization_elliott.aspx