jb ,
you're correct about " date certain " maturities . these are the fixed income issues that change every day in their price but as you said , don't effect the long term investor . you collect your dividend and get your principal in the end .
vanguard is not only inexpensive but , to my knowledge , they are the least expensive mutual fund provider . i always use vanguard as a comparison against other mutual funds cause i know vanguard is the " low cost " provider .
and you're right about not putting all your eggs in one basket . diversification is the name of the game .
i just put together a calculation for my own decision process on what n.a.v. to buy the vanguard gnma fund . if i buy that fund at $ 10.00 a share n.a.v. and the n.a.v. drops to $ 9.50 then that is a loss of 50 cents or 5 % of it's principal value . gnma's are presently paying about that yield every month so my REAL return would be zero . and because the vanguard gnma fund has fallen from it's 52 week high of $ 10.75 a share , the year to date return is negative .
if i bought that same fund at $ 9.90 and it fell to the same $ 9.50 , my loss would be 40 cents or 4.04 % and with the yield being slightly higher , my REAL return would be positive but small .
if i bought that fund at $ 9.80 a share and it fell to $ 9.50 then my loss would be 30 cents on a decline to $ 9.50 and my loss would be 3.06 % of my principal but i would have gotten a yield of 5 % durning that period and my REAL return would be about 2 % .
if i bought that fund at $ 9.70 a share and it fell to $ 9,50 then my n.a.v. loss would be 20 cents or 2.06 % and with a yield of 5 % , i would be ahead of my n.a.v. loss .
and lastly if i purchased that fund at $ 9.60 a share and it fell to $ 9.50 , i would have lost ten cents , or 1.05 % and with a yield of 5 % , i would be ahead of the game with a REAL return of 4 % .
this is the exercise one has to do when you are considering weither to purchase a fixed income mutual fund investment with a n.a.v.
of course when the n.a.v. of this same gnma is raising you not only get the yield but also principal appreciation . and for purposes of comparison , the gnma fund usually pays between 4 % and 6 % . i picked 5 % in my calculation cause it was a happy medium .
for MY money a purchase at $ 9.80 or below is a value and between $ 9.80 and $ 10.00 a share is a personal call . and those that purchased at the 52 week high of $ 10.75 are underwater at this point and likely to suffer more .
and of course this entire post is not meant to be investment advise from me or xertech but just my thoughts . you should consult your own investment advisor for specific advice .