(Adds background in paragraph 3, regulator's comments in...

(Adds background in paragraph 3, regulator's comments in paragraphs 4-5)

Oct 13 (Reuters) - Australia's ANZ Group (ANZ) acknowledged a Federal Court decision that said the bank should have advised the market of the joint lead managers bought shares in its 2015 institutional share placement worth A$2.5 billion ($1.58 billion).

The maximum penalty under the court decision is A$1 million, the country's third-largest lender said on Friday, adding that it was reviewing the judgment.

The Australian corporate watchdog in 2018 sued ANZ over the share placement, saying that the bank broke company laws by failing to tell investors that its underwriters had bought A$791 million of the A$2.5 billion shares it was trying to sell.

"The landmark case reaffirms the importance of the continuous disclosure rules to maintain market integrity," the Australian Securities and Investments Commission said in a statement on Friday.

"The decision also confirms that a significant take-up of shares by underwriters in a capital raising may be considered price sensitive information requiring market disclosure." ($1 = 1.5838 Australian dollars) (([email protected]; Twitter: https://twitter.com/sameer_manekar))