OVER-INSURED. Chubb (CB.BN) Chief Executive Evan Greenberg went back to rival Hartford Financial Services (HIG.N)two more times after an initial unsolicited offer of $65 per share in March. Hartford said on Thursday it had rejected those offers too – at $67 and $70 a share – and suggested it is worth more. Breakingviews reckons synergies from a merger might be worth around $7 billion . That means in theory they could justify a premium of about $20 per Hartford share. So far, Chubb’s best offer is about $15 above Hartford’s undisturbed value, nearly a 30% premium. On that simple math, Chubb has room to go to around $75. The $74 billion company has said, however, that it will be disciplined and investors have sent its shares down around 5% since March. And some analysts peg Hartford’s worth at $80 per share or more. In a conservative industry, Greenberg is already out on a limb making an unsolicited bid. It might be a step too far to bridge the gap. (By Jennifer Saba) On Twitter http://twitter.com/breakingviews Earlier in Capital Calls: Private pools boom read more The less flashy end of green investing read more American Airlines lightens the losses read more Europe IPOs get a qualified tech boost read more Canberra looks game for more brawling with Beijing read more