The Collaborative International Dictionary of English v.0.48:

Oversell \O`ver*sell`\, v. t. [imp. & p. p. Oversold; p. pr. &
   vb. n. Overselling. ]
   1. To sell for a higher price than; to exceed in selling
      price.
      [1913 Webster]

            One whose beauty
            Would oversell all Italy.             --Beau. & Fl.
      [1913 Webster]

   2. To sell beyond means of delivery. [Brokers' Cant]
      [1913 Webster]

   Oversold market (Brokers' Cant), a market in which stocks
      or commodities have been sold "short" to such an extent
      that it is difficult to obtain them for delivery.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "oversell":
   aggrandize, amplify, ballyhoo, be prodigal with, build up,
   burlesque, caricature, carry too far, deluge, draw the longbow,
   engulf, exaggerate, flood, flood the market, go to extremes,
   hyperbolize, inundate, lay it on, magnify, make much of,
   overcharge, overdo, overdose, overdraw, overequip, overestimate,
   overfurnish, overlavish, overpraise, overprovender, overprovide,
   overprovision, overreach, overreact, overspeak, overstate,
   overstock, overstress, oversupply, overwhelm, pile it on, puff,
   stretch, stretch the truth, swamp, talk big, talk in superlatives,
   tout, travesty, whelm