The official press release doesn’t tell us much, but Storytel Bulgaria is now officially Storytel’s 15th market, fifteen months after Storytel acquired the Bulgarian audiobook firm D&D Factory.

No numbers for Bulgarian content, but what there is will be available alongside Storytel’s 50,000 English-language titles.
UPDATE: Storytel Bulgaria launches with 300 titles in Bulgarian.
Stefan Tegenfalk, Storytel’s Head of Expansion, said simply,

Streaming services for film and music are making strong headway in Bulgaria, and we’re interested in getting involved in that development at an early stage. We have a long list of titles, everything from bestsellers to classics to non-fiction, in both Bulgarian and English. We’re constantly increasing our catalogue of Bulgarian works, and all of our approximately 50,000 English-language titles will also be available.

With this new market Storytel is now operational in Sweden, Norway, Denmark, Finland, Iceland, The Netherlands, Poland, Russia, Spain, India, the UAE, Turkey, Italy, Mexico and Bulgaria.
In an interesting twist, Jonas Tellander has updated the Storytel international site to carry just links to the fifteen existing markets and the two markets, Brazil and Singapore, that have been officially announced.

Previously the international site carried thirty country links, including the US, UK, Japan and China.

So what’s not on the new international site?
Austria, Canada, China, Czech Republic, France, Germany, Greece, Hungary, Japan, Portugal, Romania, South Africa, Switzerland, UK and USA.
Tellander has told us there will be at least six launches in 2019 and we know Brazil and Singapore are two of those. So where else might the Storytel adventure take us?
Of the countries on the old list on the international site I would rate Romania, Hungary and Czech Republic as strong candidates in Europe, with a shared language Germany-Austria dual launch a possibility, given Storytel’s Swedish rivals are targetting Germany. Given the Brazil launch Portugal must also be a strong candidate given the shared language.
My guess is neither the US nor UK are in the running any time soon despite the 50,000 strong English-language catalogue, because of rights issues with publishers who are hesitant about the Storytel royalties model. But that same catalogue may be the starting point for a South Africa launch. But maybe not in 2019.
My guess is Tellander will be looking to build on his regional hubs in Mexico and Thailand and look for a Thai launch plus one or more other SE Asia launches. I’d rate the Philippines as a strong contender given English is widely spoken there, but Indonesia or Vietnam must also be in the running.
In Latin America it seems more than probable we’ll see Storytel launch in Argentina and Colombia next year.