An estimated 2 to 3 million customer records were leaked in a data breach involving Japan’s four leading property and casualty insurers, sources close to the matter said Tuesday. Information leaked from the four firms — Tokio Marine & Nichido Fire Insurance Co., Sompo Japan Insurance Inc., Mitsui Sumitomo Insurance Co. and Aioi Nissay Dowa Insurance Co. — included customer names, insurance policy numbers, insurance types, maturity dates and premium amounts. The incident has raised concerns over lax information management practices prevalent in the industry, with suspicions that some of the l…