Nature of Business	12 Months Ended
Dec. 31, 2012
Nature of Business	Note 1—Nature of Business Tower Group International, Ltd. (“TGIL” or the “Company”) (formerly named Canopius Holdings Bermuda Limited) is a Bermuda holding company that was incorporated on September 6, 2007. As of December 31, 2012, TGIL’s sole subsidiary was Tower Reinsurance Limited (“TRL”) (formerly named Canopius Bermuda Limited), a class 3A licensed Bermuda insurance company. Canopius Underwriting Bermuda Limited (“CUBL”), another subsidiary of TGIL, was transferred to TGIL’s parent, Canopius Group Limited (“Canopius Group”), a company incorporated in Guernsey, Channel Islands, on November 21, 2012. The Company’s business operates as a single segment and considers the reinsurance it writes as originating from Bermuda. If and when the Company expands its operations, management will evaluate additional segment disclosures as required by accounting principles generally accepted in the United States of America (“GAAP”). The Company was organized to underwrite in global insurance markets by reinsuring various subsidiaries of Canopius Group that are Lloyd’s underwriting members (the “ceding affiliates”) that participate in Syndicate 4444 at Lloyd’s, through Quota Share Reinsurance Treaty Agreements (“QSRTs”). The Company reinsures each ceding affiliate for 85% of its respective participation in the 2007 year of account (“YOA”) (from October 1, 2007) and the 2008, 2009, 2010 and 2011 YOA. The Company renewed the QSRTs on similar terms for the 2012 YOA. These contracts operate on a funds withheld basis so that, generally, no settlements will take place between the parties until the YOA closes. The Company also reinsured the run-off reserves of Syndicate 839 at Lloyd’s. Syndicate 839 was closed into Syndicate 4444’s 2011 YOA as at 1 January 2011, with the treaty remaining in force through a Syndicate Limited Liability Whole Account Excess Reinsurance Treaty. Under the terms of the contract the Company has agreed to indemnify Syndicate 839 in respect of its ultimate net loss actually paid on or after 1 July 2010 up to a limit of £110m with effect from 1 July 2010. The Company provided Whole Account Aggregate Excess of Loss reinsurance cover for Acorn Corporate Capital Limited, a subsidiary of Canopius Group that was the sole underwriting member of Syndicate 839’s 2008 year of account (“the Acorn contract”). This contract was terminated by a Deed of Termination dated 10 June 2011. In 2008, the Company entered into an intermediary agreement with Canopius Ireland Limited (“CIL”), a subsidiary of Canopius Group, to write certain structured reinsurance covers sourced by CIL. Through its subsidiary CUBL, the Company also provided certain underwriting services to Syndicate 4444. The Company transferred CUBL to Canopius Group on November 21, 2012.

Note 1—Nature of Business

Tower Group International, Ltd. (“TGIL” or the “Company”) (formerly named Canopius Holdings Bermuda Limited) is a Bermuda holding company that was incorporated on September 6, 2007. As of December 31, 2012, TGIL’s sole subsidiary was Tower Reinsurance Limited (“TRL”) (formerly named Canopius Bermuda Limited), a class 3A licensed Bermuda insurance company. Canopius Underwriting Bermuda Limited (“CUBL”), another subsidiary of TGIL, was transferred to TGIL’s parent, Canopius Group Limited (“Canopius Group”), a company incorporated in Guernsey, Channel Islands, on November 21, 2012.

The Company’s business operates as a single segment and considers the reinsurance it writes as originating from Bermuda. If and when the Company expands its operations, management will evaluate additional segment disclosures as required by accounting principles generally accepted in the United States of America (“GAAP”).

The Company was organized to underwrite in global insurance markets by reinsuring various subsidiaries of Canopius Group that are Lloyd’s underwriting members (the “ceding affiliates”) that participate in Syndicate 4444 at Lloyd’s, through Quota Share Reinsurance Treaty Agreements (“QSRTs”). The Company reinsures each ceding affiliate for 85% of its respective participation in the 2007 year of account (“YOA”) (from October 1, 2007) and the 2008, 2009, 2010 and 2011 YOA. The Company renewed the QSRTs on similar terms for the 2012 YOA. These contracts operate on a funds withheld basis so that, generally, no settlements will take place between the parties until the YOA closes.

The Company also reinsured the run-off reserves of Syndicate 839 at Lloyd’s. Syndicate 839 was closed into Syndicate 4444’s 2011 YOA as at 1 January 2011, with the treaty remaining in force through a Syndicate Limited Liability Whole Account Excess Reinsurance Treaty. Under the terms of the contract the Company has agreed to indemnify Syndicate 839 in respect of its ultimate net loss actually paid on or after 1 July 2010 up to a limit of £110m with effect from 1 July 2010.

The Company provided Whole Account Aggregate Excess of Loss reinsurance cover for Acorn Corporate Capital Limited, a subsidiary of Canopius Group that was the sole underwriting member of Syndicate 839’s 2008 year of account (“the Acorn contract”). This contract was terminated by a Deed of Termination dated 10 June 2011.

In 2008, the Company entered into an intermediary agreement with Canopius Ireland Limited (“CIL”), a subsidiary of Canopius Group, to write certain structured reinsurance covers sourced by CIL.

Through its subsidiary CUBL, the Company also provided certain underwriting services to Syndicate 4444. The Company transferred CUBL to Canopius Group on November 21, 2012.