Insert your card http://beeg-hd.in.net/ beeg Retail investors, the "mom and pop" buyers who support the municipal bond market, have been shaken by shifting interest rates. In the second quarter, their market share shrank to 44.3 percent from 47.5 percent the year before, the Fed data shows. The household sector shed $32.2 billion of municipal bonds after acquiring $2.3 billion the quarter before.