Publishers have been enthusiastic about voice assistants like Amazon Alexa and Google Assistant this year, often undaunted by the fact that these platforms require bespoke content, and the route to monetization is still unclear. After promising levels of its audience returned each week to use its Alexa skill, CNBC’s global ad sales team will start selling audio sponsorship packages to advertisers in the next few months.

The company said its voice audience across Amazon and Google (on which CNBC launched in the U.S. in May) has doubled since January, though the company declined to share absolute numbers. When people interact with skills they are loyal: CNBC said audio audiences are the second most loyal behind those on its iOS and Android app. For the most part, CNBC reaches existing audiences through voice assistant devices, offering them audio content in a more useful way.

CNBC has created content for Alexa-powered devices in the U.S. since November 2016. In December, CNBC International launched an Alexa flash briefing so audiences in Europe and Asia can get region-specific updates on financial news. CNBC International’s digital team of eight people located in its London and Singapore offices are creating this device-specific content. The CNBC International Alexa skill, which audiences can use to ask for stock quotes from outside of the U.S., will launch in January.

Of course, much of this growth is due to more people owning devices, said Deep Bagchee, svp of product and technology at CNBC. Reports from Strategy Analytics found there are 24 million smart speakers globally, while forecasts from consulting firm Activate suggest smart-speaker ownership will peak at 41 million devices in the U.S. in 2019, when people will be able to access voice assistants through many other consumer products besides speakers.

“The platform is new and nascent; we want to monitor and judge how they grow,” said Bagchee. “Right now, it’s about experimentation, getting on the platform, how the features perform, how much people are consuming and what is resonating.”

With its six-person emerging platforms team dedicated to integrating CNBC’s content into new places that works closely with editorial, which produces content for the platforms, CNBC has expanded the content on audio assistant devices to offer four additional flash briefings focused on specific areas: CNBC Markets Now, CNBC Tech Check, Mad Money Cramer Remix and Mad Money Lightning Round. CNBC also creates video content for the Amazon Echo Show, some of which is produced specifically for the device. To gauge success, CNBC measures the growth of the total audience, how often people return each week and how many times CNBC’s skill is unable to answer queries. Bagchee said offering fewer features but ensuring they deliver on the user experience is the key concern.

The problem for all skills on Alexa and other audio assistants is making people aware of them. In October, Activate said more than 25,000 possible skills are available, and 65 percent of U.S. Alexa users have not yet enabled a third-party skill. CNBC has experienced this problem firsthand: As part of its ongoing audience research, when asking people what feature they would find most useful from its skill, people requested stock prices, without realizing that CNBC offers those already.

“The broader issue is around platforms educating users about skills,” Bagchee said. “Platforms need to create more awareness.” One way to address this would be for Google or Amazon to defer to a third-party skill if they don’t know the answer to a query, but how the platforms would choose or charge for this raises questions.

For next year, the goal for CNBC is more audience growth by promoting its voice assistant offering through CNBC’s other channels and creating a sustainable revenue model without compromising the user experience.

“This first year has validated the experience. We had to make sure the audience is there, and the user experience is good,” Bagchee said. “There is demand out there with finance advertisers who want to reach the audience in the tech space. Scale will be important [for advertisers], but the platform is so new there is still value in brands being associated with investing first, by crafting the right ad and user experience. We don’t want it to be audio billboard full of ads.”