Strong demand and immunity to recessions keeps investors interested in self-storage buys. : Investors are talking a good game as they negotiate to buy self-storage properties—but on average, they are still paying high prices and accepting low investment yields. “I have seen some re-trading… maybe 1.5 percent of the purchase price,” says R. Christian Sonne, director of specialty practices for the national self-storage valuation group at real estate services firm CBRE. “Property assessment reports are being reviewed a lot more closely than a few years ago.