Britain's financial services regulator has fined insurer Prudential £30m and censured its chief executive over its handling of a failed bid to acquire rival AIA in 2010.
The UK's Financial Services Authority fine concerned Prudential's plans to acquire AIA, the Asian subsidiary of AIG.
The bid eventually collapsed after both parties failed to agree on a price.
The FSA said Prudential did not inform it of the deal - even though they held a detailed meeting only weeks before news of the deal emerged.
The FSA also censured CEO Tidjane Thiam, for playing a significant part in the decision not to contact the regulator.
The regulator said the deal's size would have been the biggest in the UK and could have affected confidence in the country's financial system.