third market
noun[S]
FINANCE,STOCK MARKETukusamarketin whichfinancialorganizationsbuyandsellsharesdirectlyratherthan through astockmarket:
Thefirmis thebiggestbrokerof Eurobonds andsovereigndebtand is thelargestthirdmarketfor USequities.
Compare
fourth market
over-the-counter market
primary market
secondary market