When Steve Levitan shouts “wrap” on Modern Family's season eight finale on Friday, the cast will be without contracts to continue.

Despite the Emmy-winning comedy’s still-significant ratings, sources say its studio, 20th Century Fox Television, has yet to begin negotiating with the show’s six stars — Sofia Vergara, Julie Bowen, Ty Burrell, Eric Stonestreet, Jessie Tyler Ferguson and Ed O’Neill — for a not-yet-ordered though all-but-inevitable ninth season. The hold-up, two insiders tell The Hollywood Reporter: a fight between 20th TV and host network ABC over the cost of the long-running show.

This far into a series’ run, the network (rather than the studio) traditionally funds most of production as part of its licensing agreement; though just how much is currently in question. In the case of Modern Family, that price tag is hefty, thanks in large part to the already rich salaries being paid to the award-winning ensemble. In its eight season, which is now airing, the stars of Levitan (who is directing the season finale) and Christopher Lloyd’s hit half-hour are said to be making roughly $350,000 per episode as well as getting a cut of the series’ profits. They will no doubt demand considerably more to continue. Both the network and studio, which technically have until mid-May to make a decision about the show's fate, declined to comment.

Those cast paychecks became public ahead of Modern Family’s fourth season, when all six actors banded together and sought sizable raises. That process was neither quick nor civil, with heated talks prompting a lawsuit (the actors sued 20th TV to get out of their contracts, which they claimed violated California's law against deals lasting more than seven years) during the summer of 2012. Ultimately, the cast reached a deal that included back-end profits (a new perk for all but O’Neill) and significantly more money with each passing season; in exchange, the actors agreed to add an eighth season to their collective contracts. Later that same summer, the child stars inked raises of their own.

Modern Family’s significance to both its studio and network shouldn't be underestimated. In its eight season, the series may be down from its early years, but still it's ABC's top-rated show — and primetime's No. 2 comedy — with an average 4.0 rating among the key 18-to-49 demo. That prolonged success has translated to ad revenue, too, with 30-second spots reportedly selling for more than $200,000 this season. For 20th TV, the series is not only a calling card to help lure other creators to the studio, but a billion-dollar property courtesy of rich syndication deals with outlets including USA.

Earlier this month, reports in THR and elsewhere revealed that another long-running juggernaut (and the only comedy outrating Modern Family), The Big Bang Theory, was nearing a deal to continue after intense conversations between CBS and studio Warner Bros. TV. Key castmembers — which Modern Family's actors reportedly turned to as a model to negotiate their raises three and a half years ago — were poised to secure new contracts and the series a renewal. Multiple observers suggest they'd be shocked if ABC and 20th TV ultimately don't do the same. After all, it would be hard to believe that the network or the studio associated with the genre's other runaway hit would be ready to walk away.