People always go to the "would you buy it today" question, but I've always wondered why.
The whole point of having a well-considered investment strategy is that it prevents you from having to ask that question. There are plenty of people who, today, might say that no, they would not buy their VTSAX. That doesn't mean they should sell. It means they are spoked by market volitility. Asking if they'd buy it today and telling them to sell if they wouldn't gives them permission to abandon the "stay the course and let the market do its thing" mentality and make a decision to lock in losses.
So I think that's the wrong question. I'm not sure what the right question is, exactly, however. But I'd start with coming up with a personal investing statement, or whatever it is we are calling it these days. Completely ignore, as you write it, where your money is currently. Decide how you want to invest. Period. Once that is done, then see whether your money is currently doing what you just wrote. This sounds like a very risky, but potentially very lucrative investment. Maybe your personal statement tells you that you want 5% of your portfolio to be more aggressive. And maybe it says you want 10% of your money to be in REITs. (Maybe it says none of those things.) If it does, perhaps you sell off half of this REIT and use that money to buy a different REIT, and presto!, you've invested according to what is hopefully a rational, well-considered approach, not a frightened reaction to seeing a very red number.
(Also, it was unclear to me if you've already reached the 3 year cap gains exemption, or if you are waiting for it. Assuming it makes a significant difference, if you are close (say, 2.5 years), it might make sense to consider this, even if you decide to sell. If you are mon month 8, it probably doesn't much matter and you should ignore it entirely when selling, especially because you have no gains anyway. --This could be dependent on how losses are treated by your taxman.)
