Warren Buffett's Berkshire Hathaway, led by the group'sauto-insurance subsidiary Geico, leapt over Allstate in 2012 tobecome the second-largest P&C insurance group based on netpremiums written, according to data from SNL Financial.

Lists of the Top 100 insurance groups and insurance companies,based on total net premiums written, will be published in theJuly edition of PropertyCasualty360-NationalUnderwriter magazine.

The Berkshire group saw a 2012 increase in NPW of 12.1percent—the largest such growth in the Top 20 P&C insurancegroups. Berkshire's NPW was about $27.25 billion.

Allstate slipped to No. 3, with NPW of about $25.58 billion,which is still a 1.4 percent increase over 2011.

State Farm by leaps and bounds retained its title as the largestP&C group in 2012, with nearly $53 billion in NPW.

Of the Berkshire companies contributing to the rise in theranking is Geico, which maintained its position as thefifth-largest individual P&C insurance company whileincreasing NPW 4.6 percent. Meanwhile, Berkshire's NationalIndemnity Co. increased NPW more than 38 percent to jump four spotsto No. 7 among ranked insurance companies.

Geico Casualty Co. receives the award for the biggest jump amongindividual insurance companies. The Berkshire subsidiary was offthe list at 114 in 2011 but appears in the 60th spot in 2012after more than doubling NPW to about $1.38 billion.

It can only be assumed that Berkshire's share of the marketplaceamong insurance groups will grow with the formation of BerkshireHathaway Specialty Insurance, headed by a group of well-knownexecutives formerly of AIG. Days ago Buffett officially announcedthe launch of new commercial E&S unit BHSI, which will write property,casualty, professional and executive liability insurance andprograms in the U.S.

Peter Eastwood will lead the new unit as its president. Eastwood recently defected from AIG with fellow executivesDavid Bresnahan, Sanjay Godhwani and David Fields to join Buffett'sBerkshire.

Policies will be underwritten on the non-admitted paper ofBerkshire's National Fire & Marine Insurance Co. BHSI also hasaccess to National Indemnity, an admitted Berkshire subsidiary,when needed.