There’s a new Big Six in town. Or maybe not “in town.” But “on the planet.”

The Big Six is a term commonly used to collectively designate the behemoths of US trade publishing: Random House, Penguin, HarperCollins, Simon & Schuster, Hachette Book Group, and Macmillan. Although there are other large players, some of whom occasionally can compete with these companies for seven-figure authors, the lion’s share of the biggest author brands are published by one of these six houses.

But from the perspective of publishers or booksellers outside the United States, there is a new North American Big Six. These are the companies that have direct relationships with publishers — all of them that matter in the US (with one noteworthy exception) and, increasingly, those that matter overseas as well — to secure the rights to distribute ebook files wherever in the world the publishers have rights.

Why does this Big Six matter so much? Because as dedicated ereaders and tablets and smartphones that can effectively serve as ereaders gain increased market penetration anywhere, the appetite for ebook content will grow proportionately. In languages other than English, the number of published books currently in epub — and therefore deliverable as reflowable ebooks — is paltry compared to what we have. It will take a long time for the publishers in most countries to make enough content ready to satisfy that growing hunger in their local markets.

And the Big Six companies have the infrastructure, and, most importantly, the rights, to satisfy that appetite everywhere.

Three of the North American Big Six are well known and would be immediately identified just about anywhere. Although Amazon, Apple, and Google have not yet opened their ebook “stores” in every country in the world that can buy ebooks, it won’t be long before they will. These three global giants all derive more revenue from outside the book business than they do from ebooks (and only Amazon, of the three, has any commercial interest in selling books except for ebooks.) But they are past (Amazon), present (Apple), and future (Google) game-changers: companies that have such an enormous presence that their entry into any area, certanly including ebooks, causes every other player in the market to sit up and take notice.

There is a fourth player like them, relatively tiny Kobo,.Kobo is also an ebook retailer. Over the past two years, they have been extraordinarily successful at getting publishers to establish direct relationships with them. (I didn’t track this with great precision, but I believe Kobo was the only company besides Amazon to have all the agency publishers on board the day agency selling started last April.) Kobo has “white-labeled”, or powered, an ebook store for Borders in the US and Red Group in Australia (two booksellers who, coincidentally or not, have just filed for bankruptcy protection). Kobo also has, according to their executive, Michael Tamblyn, at Tools of Change, “more than two million registered users.”

All four of these companies will be competing as ebook retailers in every market in the world and in every language in the world. They all start out with a robust aggregation of US-published ebooks. Apple is the laggard here. They don’t carry Random House books yet — the “noteworthy exception” referred to in the third paragraph above — and they have fewer available titles than any of the other three. But Apple comes with its own significant advantages in the form of the wildly popular iPhone and iPad. These devices assure a certain minimum amount of traffic to their iBookstore, even if Apple doesn’t move ahead with in books with the power play they’ve just exercised over subscription sellers of magazines and newspapers. (And so far we have only rumors and stretched intepretations of what they’ve said and done to suggest that they will do that anytime soon.)

Because American hegemony is resented in much of the world, Kobo may have a built-in advantage in international competition against the other three. Kobo is a Canadian company. They are also not disrupting people’s lives or terrifying them by monopolizing online print sales in any market (like Amazon), or by delivering devices designed to capture audiences and wall them off from competitors (like Apple), or by digitizing first and asking permission later (like Google.) All three of the Biggest Three (of the Big Six) have enemies and detractors. Kobo doesn’t.

Kobo doesn’t have their effectively unlimited resourcces either.

There are already retailers active in every country in the world, operating in the local language, who want to be the ebook resellers of choice in their own countries. For them, the other two members of the North American Big Six are potentially critical resources: Ingram and Overdrive.

Ingram is well known throughout the book business worldwide (and is sometimes, and currently, a client of ours.) As the biggest and most innovative wholesaler in the US for four decades, they have built both a customer base and a supplier base all over the world. They’ve been the principal wholesaler of ebooks to US independent ebook retailers since the begining of ebook time. They have deep and strong relationships with every US publisher of any size, rooted in their wholesaling business. They can set any retailer up with a wide selection of US ebook titles.

Ingram’s competitor for the role of delivering English-language (and, ultimately, all non-local language) ebooks to resellers all over the world is Overdrive. Overdrive has been in the digital content business since the 1980s and pioneered ebook distribution to libraries from the dawn of the current ebook era in the late 1990s. They also have a very broad base of publisher suppliers and can, like Ingram, provide an ebook reseller local to any country with a robust selection of other-language ebooks to vend, with an emphasis on those provided by American publishers.

Could any upstarts join the Big Six as credible providers for local competitors to the four global ebook retailers? I see three possibilities.

Barnes & Noble certainly has the relationships with publishers globally to assemble an ebook title selection that can rival anyone’s (and they’ve done it.) They are already the number two ebook reseller in the US market, miles ahead of Apple and Google and Kobo. But, so far, they have continued their brick-and-mortar strategy of sticking to the US market. It seems to me that the economics of their successful Nook family of devices and the ebook store they run would benefit from extending to a global base. But every company has to make choices about resource allocation and focus, and it is hard to quarrel with the success B&N has had competing with Kindle and iPad considering their prior experience with hardware (none). They’ve leveraged their retail presence to do it and they don’t have that resource to employ outside the US.

Copia and Blio are upstart ebook platforms. The independently-owned Copia has its social component as a unique feature (although Kobo has some pretty cool social stuff and there’s an upstart called Rethink Books with some technology that provides social capabilities around books independent of the ebook platform.) When Blio started, they seemed to offer an opportunity for publishers to enhance their ebooks readily. But the tool set that would enable hasn’t been delivered. Both of these offerings have a distance to travel to catch up with the Big Six, all of which have been in the game a long time and built up a network of suppliers and customers that it is not a trivial challenge to duplicate.

If there’s going to be a Big Seven, my bet would be on B&N.

Right now, publishers and retailers seeing the book tsunami coming closer to their shores will want to focus on the North American Big Six. If I were a publisher in any language, I’d be sure they all had my books. If I were a retailer in any country, I’d be looking at them as possible competitors or collaborators. Understanding who these companies are, what they have to offer, and what they have in mind is going to be an important component of every publisher’s and retailer’s strategic thinking for the foreseeable future.