How exactly are George's songs affected by Sony/ATV holdings..? Are Harrisongs, Ltd (which I believe hold the publishing rights for all songs done after '68) affected or doesn't Michael Jackson have any management rights over them, which would add a layer of difficulty if later albums like 'Abbey Road' went to iTunes.
This is an excellent question, as it speaks to the issue of how Beatles music is released (or alternatively, why Beatles material often isn't released). As far as I know, there are three levels of approval required for a Beatles recording to be used commercially:
1. Copyright of the sound recording: EMI owns all of the Beatles' master tapes, and thus must give permission for them to be used. EMI has in the past suggested compilations (e.g. Sessions) that were never released due to #3 below. Note that this does not apply when only a Beatles song being used (i.e. a cover performed by another artist), in which case only #2 applies.
2. Publishing rights: Sony/ATV, as you point out, controls most of the Beatles' songs in terms of music publishing. The exceptions are Harrisongs Ltd. (post-1968 George Harrison songs), Startling Music (post-1968 Ringo Starr songs), and MPL Communications ("Love Me Do" and "P.S. I Love You"), which are controlled by the individual Beatles or their estates.
3. The Beatles/Apple: The four Beatles (or their estates) must approve any official Beatles products before they can be released. From most written accounts I have seen, this has been the major barrier in getting Beatles music released. While some compilations have been approved and released (Let It Be...Naked, 1, Love, etc.), it has been slow going in other areas (getting the full catalogue remastered, releasing Let It Be on DVD, getting Beatles music on iTunes, etc.).
So, to answer your original question, George's songs from 1963-1968 are controlled by Sony/ATV (a company co-owned by Sony and trusts formed by Michael Jackson), while from 1969 onwards they are controlled by the Harrison estate through Harrisongs Ltd. So that would mean that for Abbey Road to be included on iTunes, for example, you would need to secure the publishing rights from Sony/ATV (for Lennon/McCartney songs), Harrisongs (for George's songs), and Startling Music (for "Octopus's Garden"), plus approval from EMI and Apple. The inclusion of Harrisongs in the equation, to my mind, does not add a layer of difficulty, as you would already need to secure permission anyway from the Harrison estate (as part of #3) for any Beatles material to be released.
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