When a broker finds a potentialmutual fund investor who balks at thebig upfront sales load that A sharescarry, the solution is to change the pitchto B shares, which have no front-endsales fee. Buyers beware, some marketmavens say. To make up for the loss ofthe front-end sales charge, B sharescarry higher annual expense ratios andusually have a back-end load, whichmeans you pay out a percentage of yourportfolio when you sell. Buyers who arelured by these apparent no-load securitiesmay find themselves stuck in anunwanted investment unless they wantto pay the back-end charge. Although Bshares do put your full investment towork immediately, some financial analystsexplain, higher expenses and backendloads make them a poor investmentidea over time.