Maybe not so mysterious. RSO has tracked (more or less) with the overall REIT watchlist I look at each day. Most every REIT (not just agency) has been getting a beatdown the past two weeks. In some ways, RSO has held up better than most. Look at how bad NRF as fallen for example. Today though, almost every REIT is up a lot. There are a lot of funds that do basket trades, trading a whole bunch of different stocks all operating in a similar sector. RSO gets caught up in this basket, and being a smaller REIT can make volatile moves.