AsianFin -- Nvidia Corp. disclosed that two unidentified customers accounted for nearly 40% of its record second-quarter revenue, underscoring how concentrated demand has become amid the artificial intelligence boom.

In a filing with the Securities and Exchange Commission, the chipmaker said one customer represented 23% of total revenue in the three months ended July 27, while another made up 16%. Together, the two generated 39% of Nvidia’s $46.7 billion in quarterly sales, which jumped 56% from a year earlier.

The company did not name the buyers, referring to them only as “Customer A” and “Customer B.” During the first half of the fiscal year, the same clients contributed 20% and 15% of revenue, respectively.

Nvidia added that these are “direct” customers — including equipment makers, distributors, and system integrators — rather than the cloud service providers and consumer internet companies that typically source its chips through intermediaries.