Tower increased its provisioning from $3.1 million to $19.7 million.
Flannagan said the adjustment was due to higher than expected rebuild costs and a slowdown in dealing with the EQC after privacy breaches.
"All of those things are factors."
He now believed the provisioning was sufficient and the company was in a good position to focus on growth.
Last week shareholder Devon Funds Management, which owns 8.6 per cent, said Tower was at risk of being a takeover target because of its low valuation compared to Australian insurers and high cash position.
But Flannagan said potential buyers were probably being scared off by the Christchurch situation. However, as a listed company he admitted it did not have any control over its shares.
Guinness Peat Group, which owns 34 per cent of Tower, has made no secret of its desire to exit the business.
Flannagan said the growth of the company rested with its leadership. The board has been refreshed in the past year and Flannagan said an announcement regarding his replacement was imminent.
Shares in Tower closed up 15c yesterday on $1.85.