Migdal Insurance (TASE: MGDL ) has asked a third party to reassess the value of its 8% stake in Bank Leumi (TASE: LUMI ) . That figure excludes the 1.5% equity held by subsidiaries. The insurance company did not write down the value of its Bank Leumi shares in its second-quarter financial statements. The gap between their book value and their actual market value is NIS 300 million Migdal has them registered as being worth about a billion shekels, whereas their market value today is NIS 701 million. In its second-quarter statement, Migdal wrote that it does not believe the slide in Leumi's market value is due to a permanent erosion of its value. It also notes, however, that the state's impending offering of a 6% to 7% stake in the bank could be at a share price lower than that stated in Migdal's books. Market sources surmise that Migdal's move was prompted by the Israel Securities Authority.