Among agents it's been a longstanding truism—and occasional source of irritation: several big players still charge authors a 10% commission instead of the standard 15%. Now it seems like that may be changing.

Sources say that over the last few months, William Morris and ICM have adjusted their rates from 10% to 15%, leaving very few charging the lower percentage. Officials at William Morris and ICM were not immediately available for comment.

Agents are split on the consequences of the move. Some feel these firms are merely catching up to the rest of the industry—and that it will produce little realignment. "It's possible the change would shake loose some clients who were unhappy anyway, but if someone is really looking for 10%, they'd have a hard time. There are just not very many places they could go," said agent Donald Maass.

But others say it strikes a blow for parity. "If you get into a beauty contest with someone at William Morris, it's been a tremendous competitive advantage for them to charge only 10%," said Christy Fletcher of independent agency Carlisle & Co. Indeed, one agent at William Morris said that a prospective client chose not to sign on after being told there was no wiggle room on the new rate.

Publishing insiders seem similarly divided on the logic of the decision. Some argue that the changing role of agents more than justifies the shift. "It was an archaic commission scheme. Things have gotten more complicated and agents do a lot more [than when the 10% was standard]," said William Clark, a William Morris veteran who now runs his own agency.

Many on the author side, however, say the move's timing raises questions. "You have to look at what are they doing to justify the extra 5%," said the National Writers Union's Jonathan Tasini. "If you've been taking 10% doing certain things for your client and suddenly you're taking 15%, it would seem to me that you'd need to explain that 50% increase. Are you doing something more or it just a way to make more money?"

Almost everyone agrees the change is a sign of the times—a more overt nod to the bottom line amid a downswing that has hit even the profitable agent sector. Some also suggest that the firms chose to change the rate now because contracts involving Hollywood, which are constrained by stricter rules, are changing, giving the firms more latitude.

One consequence that few wanted to speak about publicly is whether the increase provides cover for other agencies to raise rates further. Privately, some say it's already an open secret that commissions on film deals involving a number of co-agents can go as high as 20%. And while that figure seems high, they point out that those who hiked the number from 10% to 15% also faced heat at first.

Of course, it's an equally open secret that official rate cards aren't always so official. It's the size of the deal, not the percentage of the cut, that often matters most. As one agent said, "I'd rather have 5% of Nelson DeMille than 15% of a lot of other people."