Len Blavatnik’s Access Industries is buying Warner Music Group Corp., the world’s third-largest recording company, for about $1.3 billion, according to a person familiar with the matter.

The person, who was not authorized to speak publicly about the matter and spoke on condition of anonymity, said the deal was expected to be announced later Friday.

The purchase, for $8.25 a share, comes amid a global decline in CD sales that continues to weigh down the industry. The buyer will also assume about $1.9 billion in debt.

U.S. recorded music sales are half what they were a little over a decade ago. Digital sales gains have started to flatten and CD sales continue to fall.

That means Blavatnik, a former board member who was part of the group that bought the company in 2004 and still has about a 2 percent stake, will have to cut payrolls further and hope that a new wave of innovation will carry digital music sales higher.

The sale ends a seven-year run by investors led by CEO Edgar Bronfman Jr., who purchased the company from Time Warner Inc. with private equity backing for $2.6 billion. Those investors slashed payrolls and took other measures to cope with music’s decline. They took the company public a year later to help recoup their investment. There are now just 3,700 employees, down from 5,100 in late 2003.

The Russian-born Blavatnik, 53, will likely have to cut even more — so much so that billionaire Ron Burkle balked at pursuing the company past an initial round of bidding, because cuts might start to hurt Warner-signed artists he considers friends, such as Red Hot Chili Peppers, according to another person familiar with the matter who wasn’t authorized to speak publicly.

The fortunes of the music market remain uncertain and last year, rising download sales have been offset by the collapse in the popularity of ringtones.

The new owner may have to bank on new services yet to take off. There’s speculation that Google Inc. is coming out with a music service, and Apple Inc. with unveil a subscription plan to complement sales of individual tracks on iTunes.

Further deal-making is possible. Citibank is looking to sell Britain’s EMI Group Ltd., which it seized from Guy Hands’ Terra Firma private equity group in February after it defaulted on a loan.

Other groups that lost out on bidding for Warner — including No. 2 Sony Corp. — are also looking for parts that may be discarded from this deal.

In one possible scenario, Warner’s new owners would make a play for No. 4 EMI in order to reap the benefit of slashing staff at a combined company, and then shed certain music labels or get rid of one of the publishing divisions to satisfy antitrust regulators.

Vivendi SA’s Universal Music Group, ranked No. 1, is also looking to snap up parts of Warner, EMI or both.