I'd question why the market has dropped its discount rate for my thing so drastically! In theory, a market price is essentially the net present value of all future payments, discounted to current dollars. In practice, the discount rate used often swings wildly - both due to changes in opportunity cost, but also due to the psychology of markets.
In your example, what was a 4% yield on valuation has dropped to a 1% yield on valuation. That would mean to me that the market thinks that some mix of the following are happening:
- The opportunity cost of capital has dropped a lot (this is the same theory of share prices rising when interest rates drop).
- There is an expectation that future cash flows will rise
- The market for my thing has taken on a "greater fool" approach - i.e. people begin to speculate on the premise of further capital gain (Aussie housing, anyone??)
In your example where the price has appreciated so much, and the income not so much, I'd probably end up re balancing some of my appreciated "things" into alternative things!