Yep. NEVER BUY A HIGH PROFILE IPO! Think about it. Everyone who wanted to buy Twitter stock bought yesterday - so there are no more buyers left. When you have a market with no buyers, only sellers, which way does the stock price go?
Facebook was the same way. Out of the gate, the stock went down. It's rallied this fall, but I think Facebook (and Twitter) probably are on the way out. What's the average lifespan of a social media website? Ask Myspace. (With Facebook, I think Zuckerberg knew his website was on the way out, and he went public with it so he could become a billionaire while he still had the chance.)
The dividend yield is around 14% - which is insane. With a dividend yield that high, the company should be trading at about 5 times it's current price. A stock price of $111.35 would drop the dividend yield down to about 2.80% which is a lot closer to, say, the dividend yields of stocks in the DJIA.
But if the value of their assets keeps going down (as you say), that explains why the stock is not going up. Maybe what is going on is Wall Street is leery of buying more of this stock since its assets are shaky - yet Wall Street can't bring itself quit American Capuital Agency's huge dividend payments. So the stock goes sideways.