NEW YORK — The chairman of the Securities and Exchange Commission is likely to face an especially tough hearing in front of Congress, after the agency acknowledged that it also was a victim to a hack.

News about the breach of an SEC network that delivers company news and data to investors follows the disclosure of the massive data breach from credit company Equifax.

Jay Clayton, who has been at the head of the SEC since May, is not likely to face calls for his removal since the breach happened a year ago, before he was sworn in.

But he may be questioned about whether the SEC — the federal government’s main arm for enforcing rules and regulations on Wall Street — is up to the task of keeping data secure.