SAN FRANCISCO — One of the poorest-kept secrets in Silicon Valley has been the huge salaries and bonuses that experts in artificial intelligence can command. Now, a little-noticed tax filing by a research lab called OpenAI has made some of those eye-popping figures public.

OpenAI paid its top researcher, Ilya Sutskever, more than $1.9 million in 2016. It paid another leading researcher, Ian Goodfellow, more than $800,000 — even though he was not hired until March of that year. Both were recruited from Google.

A third big name in the field, the roboticist Pieter Abbeel, made $425,000, though he did not join until June 2016, after taking a leave from his job as a professor at the University of California, Berkeley. Those figures all include signing bonuses.

The figures listed on the tax forms, which OpenAI is required to release publicly because it is a nonprofit, provide new insight into what organizations around the world are paying for A.I. talent. But there is a caveat: The compensation at OpenAI may be underselling what these researchers can make, since as a nonprofit it can’t offer stock options.