When the digital news start-up Semafor began in 2022, its founders talked about reaching a vast global audience of 200 million college-educated, English-speaking people.

But their latest push is aimed at just a tiny — albeit moneyed — sliver of that: top executives.

The company said Thursday that it would start an invitation-only newsletter for chief executives, The CEO Signal, in January. It will be free but available only to the leaders of companies with more than $500 million in annual revenue.

Semafor’s newest project is the latest in a series of moves among media outlets like The Wall Street Journal, Axios and Fortune, which are battling for attention inside the C-suite.

Despite a crowded marketplace, each sees an opportunity for its newsletters and events to cater to the highest echelon of corporate leaders and to tap into a lucrative world of sponsorships and subscriptions. New sources of revenue have become increasingly important for many publications in the face of a tough digital advertising market and faltering social media traffic.

“It truly is an example of the reversal of this 20-year trend in media of prioritizing scale,” said Justin Smith, the chief executive and a co-founder of Semafor. He added, “We’re really not talking about small business or midsize business but the C.E.O.s of the biggest companies in the world, which is a micromarket.”

Mr. Smith said he had realized shortly after Semafor began that its journalists and articles were “tilting our whole model, at least in the initial phase of Semafor’s existence, toward a very, very clear audience segment, which I would call the global leadership class.”