For roughly half a century, John Fogerty had tried to recover the rights to dozens of hits he wrote for Creedence Clearwater Revival. At the age of 77, he had almost given up hope, when he and his wife, Julie Fogerty, who also works as his manager, realized they were on the cusp of a second chance thanks to the Copyright Act of 1976.

That law–specifically sections 304(c) and 203–are intended to give musicians, songwriters and other creators a second bite at the apple by enabling them to recapture the copyrights to compositions and recordings, in the United States only, that they may have signed away earlier in their careers. Songs dating from before 1978 can revert to their creator or heirs after 56 years, and songs from after 1978 can revert to the creator or heirs after 35 years, provided they file the proper paperwork.

Realizing that many of John’s songs were nearing that 56-year threshold, Julie reached a deal with Concord in January that returned majority control to her husband of worldwide publishing rights to over 65 Creedence classics.

Although clearing the legal and corporate hurdles to recapture rights can be significant and compromises are often negotiated, some industry insiders say that same law could lead to artists putting up for sale their newly recovered catalogs in a way that stokes the already hot market for publishing and recording rights.

“You have this interesting confluence of the big, big moment in classic rock, and you’re also getting to the 35-year window for late-1980s songs,” says Concord CEO Bob Valentine, who mentioned the mutually “happy outcome” with John during a discussion about works from the late ’60s and late ’80s approaching their reversion dates.

“Those are two huge windows for multiple genres,” he adds. “It makes the [catalog investment] market really interesting at this moment in time.”

Clearing the hurdles — both within the law and presented by music companies — to recapture rights is complicated, but there is some precedent to support this optimism. In 2013, when the first wave of post-1978 works approached the 35-year threshold, Billboard reported that nearly 20 of the world’s most famous songwriters had filed termination notices with the U.S. Copyright Office, including Paul McCartney, Bob Dylan, Brian Wilson, Gerry Goffin & Carole King, Willie Nelson, Daryl Hall & John Oates and the estates of Buddy Holly and Bo Diddley.

Lisa Alter, a founding partner at Alter Kendrick & Baron in New York and an expert in rights reversion negotiations, says a new surge has already begun. “Commerce has definitely increased in this area,” she says. “It will continue to increase, and at some point, maybe 10-plus years down the line, things will start to level off.”

Sources cautioned, however, that rights reversions — particularly for master recordings — rarely work out so cleanly as the law implies, and that likely only a fraction of the hit song catalogs reaching the 35-year or 56-year milestones will revert to their owners.

While John was able to regain a majority share of his worldwide publishing rights, Concord retains the Creedence master recordings in its catalog and, as of January, was still administering the rocker’s share of the publishing catalog. (Concord obtained Creedence’s recordings through the 2004 acquisition of Fantasy Records.) While John regained only publishing rights this year, Concord reinstated and improved his artist royalties shortly after the acquisition.

A key argument used by industry observers who predict the spate of copyright reversions will superheat the catalog investment market in the coming years is that superstar artists and songwriters who were behind hit records in the ’60s, ’70s and ’80s are aging and may be considering selling their rights to pass down a simpler inheritance to their heirs.

Before that can happen, however, artists and songwriters — or their heirs, if they are deceased — are required to serve the U.S. Copyright Office and their current music publisher or record company a termination notice at least two years before the songs turn 35 or 56, and they cannot enter any agreement with a third party before their current contract is terminated. Whoever has been holding those rights has the right of first refusal to acquire them.

While that option often leads the incumbent rights holder to negotiate new deals with the artists seeking to recover their rights, Alter says that since 1978, publishers have usually acquiesced when artists seek to reclaim their publishing rights, and labels have largely sought to block attempts to reclaim sound recording rights.

“There has been almost universal opposition on the part of the labels to the [termination] notices,” she says, with labels often arguing the notice was not validly served or the artist or songwriter produced the song as a work for hire. “While some artists have successfully gotten their rights back, in the majority of cases, the record label has renegotiated the leases.”

Many artists have attempted to sue major labels for their responses to termination notices — so far almost always unsuccessfully. One closely watched case was brought by “Missing You” singer John Waite, who sought class action status for hundreds of artists to sue Universal Music Group to regain control of their masters. The class action request was denied in January after a judge said there were complex and unique issues raised by each artist’s relationship with UMG that could not be resolved on an “aggregate basis.”

Round Hill Music co-founder Josh Gruss, who was an early investor in songs as an asset class, says he questions whether the rights reversion trend will result in more copyrights coming to the investment market.

“It’s really hard for significant recordings to fall out of the major-label system,” he says.

That said, Gruss acknowledges that attractive copyrights that have reverted to an artist or songwriter frequently come up for outside investment. For example, songwriter Eddie Schwartz, who wrote 100% of Pat Benatar’s 1980 top 10 Billboard Hot 100 hit “Hit Me With Your Best Shot,” reclaimed his publishing rights to the song in 2015 and sold them to Round Hill. Gruss says they’ve both been happy with the result.

When it comes to master recordings, however, Gruss agrees with Alter’s assessment.

“The labels have always done a masterful job of not letting the recordings revert,” he says.