For high yields bond funds, the NAV value really doesn't represent the profit or loss to investors like a growth stock. Here you get a quite high income monthly distributed to you and reinvested in additional shares. The NAV price doesn't include the distribution of this "dividend" (interest). As a matter of fact, the principle of the dollar-cost-averaging increases you profit EVEN THE CURRENT NAV IS SLIGHTLY BELOW the PEAK NAV several years ago. Because, when you sell you entire holding after several years, your cost basis (and of course, the total number of shares) would be far more than your initial investment due to the additional shares you "acquired" through the holding period. Furthermore, if during holding period, the NAV values fluctuated from going-down then up again, you would have more gains than if you bought a low dividend stock through the same time period. Even in some of the stocks or partnership, the companies occasionally will distribute shares or split, then the stock price or the NAVs or prices wouldn't be comparable between the NAV before and the NAV now.