Risk managers are keeping careful watch on insurance market premiums, wondering how long they can enjoy the soft pricing that has been in place since 2004. Advisen, a New York-based insurance information and advisory firm, puts a number on that question, noting that it's an overabundance of supply that limits property and casualty insurers' ability to raise prices, in the form of $74 billion of excess capacity.

Meanwhile, the sluggish economy is limiting the demand side of the equation, according to Advisen's analysis.

Advisen says that excess capacity could be wiped out by a single "mega-catastrophe" or a number of smaller catastrophes, but argues that the more likely scenario is a slow erosion as the low level of premiums takes its toll on insurers' capital.