It’s not a long line of dominos – just three in particular – but if they begin to fall you can bet there’ll be collateral damage throughout the radio industry.

The most wobbly of the three is Cumulus Media. The #2 radio station conglomerate in the country by stations owned, the company just can’t get a break with its turnaround endeavors. After an 8-to-1 reverse stock split last year which temporarily raised its share-price above the critical $1 floor for listing on NASDAQ, the company’s gone underwater again. Thursday’s trading-close saw CMLS shares at just under 27 cents, making for a total market capitalization just above $8 million. That’s about half of what it was just a month ago. Earlier this month, NASDAQ started the delisting-clock again, which means Cumulus has six months to implement a revival-plan and stick to it.

Of course, the aggregate value of Cumulus’ hundreds of radio station licenses is multiples higher than the market value of its stock, but most definitely not enough to cover the $2+ billion in debt it carries. A refinancing proposal using stock imploded last month, prompting Bill Cunningham in Media Life (just before it shut down) to observe that “Unless some white knight comes along, Cumulus has no choice but to file for bankruptcy protection. It could come in a matter of weeks.”

“Weeks” is doubtful, although Moody’s Investors Service just last week downgraded Cumulus’ credit ratings to levels that translate to “extremely speculative” and “default imminent with little prospect for recovery.” Moody’s own words cite an “elevated risk of a restructuring” and an “unsustainable” debt ratio. However, it expects a “pending asset sale,” details unknown but slated for the “second half of 2017,” to provide a much-needed cash-infusion. We shall see.

Although Cumulus is the one who seemes closest to the brink, did iHeartMedia quietly cross it last month when it annnounced a “global restructuring of its indebetedness“? This refers to two new debt-refinancing offers it’s made, which were the subject of a smart takedown in the New York Times by Seton Hall Law School bankruptcy expert Stephen Lubben: “This new exchange offer is as much about equity salvage as debt restructuring,” he concludes.

Moody’s called these new offers “a continuation of its distressed exchange,” and although the iHeart-owned trade publication Inside Radio crowed about its short-term effect on IHRT’s stock-price, there were literally no takers. So the company’s extended the offer until the end of this month. What happens next if the market continues to shun iHeart and Cumulus’ debt-dance moves?

The third domino is one that’s received little media attention: the Spanish Broadcasting System. This company, founded in 1983, has a big piece of the Spanish-language radio pie, owning 17 stations in major markets (Chicago, Los Angeles, Miami, New York City, and San Francisco) and Puerto Rico, as well as stakes in program-syndication, television and live-event production. But the company’s also subscribed to the philosophy of leveraged growth, taking on more than a half-billion dollars in debt – $275 million of which is due this month.

As this deadline has approached, SBS stock has taken a beating; last year it was delisted from NASDAQ and began trading this January on a secondary exchange. Now that exchange has warned SBS that it could be delisted within six months, given that its market cap has fallen below the $5 million dollar minimum floor (SBSAA closed Thursday at 56 cents a share, for a total market capitalization of just $3.6 million).

In the FCC’s just-concluded reverse auction of television spectrum (to be repurposed for wireless broadband service), SBS put its TV channels on the block, hoping for tens or hundreds of million dollars in return. But just one of its channels sold in Puerto Rico for less than $5 million.

Before bankruptcy would come to pass, it’s highly likely that Cumulus and SBS would find themselves targets of an acquisition of sorts; smaller-fry such as Beasley and Greater Media could team up to divvy Cumulus stations between them, with Entercom – newly beefed-up by its acquisition of CBS Radio – possibly skimming some cream. SBS, as the #5 player in the Spanish-language radio space, would be easy pickings for bigger fish such as Univision or Entravision – who racked up $86 million and $263 million respectively in the FCC’s TV reverse auction.

The entire U.S. radio industry’s annual revenues aren’t big enough to absorb the $20+ billion in debt that iHeartMedia has. There seems to be little left to do other than watch the slo-mo implosion and the reverberations it’s likely to have across the entire sector; much less a question now of if than when. It will make for the single greatest shakeup in radio ownership since the industry’s consolidation-orgy in 1996 – the bitter fruit of a wild ride with other people’s money.

Much hay’s been made recently of a Bureau of Labor Statistics report showing that the publishing industry has contracted dramatically this century, with newspapers cutting staff by more than half in the last 15 years alone. Time hasn’t been kind to radio, either, which shed more than 26,000 jobs – nearly a quarter – during the same timeframe.

A re-valuation of radio finance will undoubtedly be disruptive. What’s next, the Uber-like contracting-out of radio content to podcasters, algorithmically-assembled into “formats,” doing away with the pesky necessities of studios and offices completely?