According to the free online encyclopedia Wikipedia (http://en.wikipedia.org/), a host of record labels that were once part of smaller companies or independent altogether are now part of the 'Big Four' record companies, which hold 70 percent of the music market share worldwide (a $30 to $40 billion industry in 2004).
Universal Music Group ($7 billion in revenue) includes A&M, Decca/London Deutsche Grammophon, Island, MCA, Motown, PolyGram, and others.
Sony BMG Music Entertainment ($9 billion), which as of August 2004 consisted of the merger between Sony Music Entertainment and BMG Entertainment, includes Columbia, Epic, Arista, RCA, and others.
EMI Group ($4 billion) includes Angel, Blue Note, Capitol, Odeon, Parlophone, Virgin, Positiva, and others.
Warner Music Group, a.k.a. WEA ($2.5 billion) includes Warner Brothers, Elektra, Atlantic, London, Reprise, Rhino, and others.