Over the next two decades, ATV expanded through acquisitions to become an entertainment conglomerate with business lines in the record industry, music publishing and film production.

Northern Songs was co-owned by Lennon, McCartney, Brian Epstein and Dick James, who owned a controlling interest.

The financial clout of Grade, their adversary in the bidding war, ensured that the songs written by the two Beatles passed into the control of ATV.

ATV Music also entered into co-publishing agreements with Lennon and McCartney, whose contract with Northern Songs expired in 1973.

While ATV Music was successful, its parent company, now known as Associated Communications Corporation (ACC) began experiencing financial difficulties.

McCartney, with Lennon's widow Yoko Ono, offered £21 million but the offer was declined by Grade who decided not to sell Northern Songs separately after other suitors, including CBS Songs, EMI Music Publishing, Warner Communications, Paramount Pictures and the Entertainment Co. showed interest in buying ATV Music as a whole.

[8][9] Meanwhile, Australian businessman Robert Holmes à Court had been acquiring shares of ACC and launched a takeover bid in earnest in January 1982.

Grade resigned as chairman and was replaced by Holmes à Court who successfully acquired a controlling interest in the company.

One evening while at the dining table, McCartney brought out a thick, bound notebook displaying all the songs to which he owned the publishing rights.

The two sides signed a non-binding memorandum of mutual interest in December 1984 and Jackson's team began a four-month process of verifying ATV Music's legal documents, financial reports, and every significant composition in the nearly 4000-song catalog.

Jackson's team thought they had reached a deal several times, but new bidders would enter the picture or they would encounter new areas of debate.

Jackson only raised his bid to $47.5 million, but he had the advantage of being able to close the deal faster, having completed due diligence of ATV Music prior to any formal agreement.

[12][14] In October 1985, Jackson fulfilled his contract provision to visit Perth, Western Australia and appear on the telethon, where he spoke briefly and met with two children.

[17][18] Jackson went on to use the Beatles' songs in numerous commercials, feeling that it would enable a new generation of fans to enjoy the music.

[14] Privately, Jackson was reported to have expressed exasperation at McCartney's attitude; he felt that the musician should have paid for the songs he had written.

But he was a lovely man, massively talented, and we miss him.Ono was pleased that Jackson had acquired Northern Songs and called it a "blessing".

'"[14] At least one Beatles song was covered by Jackson after acquiring publishing rights: "Come Together" from the album Abbey Road (primarily a Lennon composition) in 1986.

The song was recorded for Jackson's 1987 album Bad but was scrapped and instead put on HIStory: Past, Present and Future, Book I eight years later.

[24] Michael P. Schulhof, President and CEO of Sony Corporation of America, welcomed the merger and praised Jackson for his efforts in the venture.

"[25] He added that Jackson recognizes Sony's "leadership in developing and realizing new technologies that serve to expand the creative horizon of artists such as himself".

[24] In 2006, Sony gained operational control of Sony/ATV and obtained an option to buy half of Jackson's stake in the company at any time for a fixed price of $250 million.

In November 2001, the company signed country singer Tony Martin to an exclusive songwriting and co-publishing deal.

Through the deal, they acquired Martin's Baby Mae Music catalog of 600 songs, which includes Joe Diffie's "Third Rock from the Sun" and Jeff Carson's "Not on Your Love".

[35] "As a music publisher, we are always looking for new and innovative ways to promote our songs and songwriters," Sony/ATV chairman and chief executive David Hockman announced in a statement.

[35] On August 4, 2008, The Orchard secured a deal to globally digitally distribute and market the music catalog by Sony/ATV which includes: Sony Tree Productions, Hickory Records, and Masters International.

Sony/ATV became the largest music publisher administrator company in the world with more than 3 million songs[46] and estimated revenues of over US$1.25 billion per year.

[47] After the acquisition, three EMI executives joined Sony/ATV international leadership team: Guy Moot, president of UK and European creative; Susanna Ng, Asia managing director; and Clark Miller, executive VP of international business affairs and global opportunitites.

[51] The acquisitions would put the Columbia-Screen Gems catalog back under common ownership with Columbia Pictures, which had sold the rights to EMI in 1976.

[53] In January 2017, McCartney filed a suit in United States district court against Sony/ATV Music Publishing seeking to reclaim ownership of his share of the Lennon–McCartney song catalogue beginning in 2018.

[56][57] A recent and relevant valuation is tied to Sony's acquisition of Jackson estate's stake in the company, completed on September 30, 2016[53][58] for $750 million.