I suspect some of the recent decline is due to tax loss selling. NLY is a perfect candidate. It is down substantially year-to-date in a year that was very strong to the upside (i.e. tax losses are very attractive due to market gains) In addition, tax-loss opportunities are somewhat limited due to the broad advance in the general market. Furthermore, NLY is down significantly since the start of November (the time end of year tax planning begins in earnest) and it is also down substantially over the past several years (meaning that almost all long-term holders are sitting on a substantial loss that can be harvested). There are not many stocks that fit this profile.
It I am right, we should see continued declines till about mid December followed by a nice rally through the month of January.