NEW YORK (CBSNewYork/AP) — James Dolan, the owner of the New York Knicks and New York Rangers, has agreed to pay more than $600,000 in civil penalties for running afoul of federal securities law.

The Federal Trade Commission said Thursday that Dolan failed to notify federal authorities after acquiring additional stock last year in the Madison Square Garden Company.

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A company spokeswoman, Kimberly Kerns, attributed the fine to the failure of a law firm to meet filing deadlines related to Dolan’s stock. She said the law firm agreed to pay the fine “as a result of their mistake.”

Federal law requires antitrust notifications when the acquisition of voting securities exceeds a certain threshold.

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The U.S. Justice Department said in court filings that the penalty was adjusted downward because it was inadvertent and “promptly self-reported.”

The court filings said Dolan committed a similar violation in 2010 when he acquired stock in Cablevision Systems Corp, where he served as chief executive officer. He was not fined for that violation.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)