Exhibit 99.1

Tower Group Reports Third Quarter Results

NEW YORK – November 7, 2012 – Tower Group, Inc. (NASDAQ: TWGP) today reported third quarter 2012 net income attributable to common shareholders of $21.6 million, or $0.56 per diluted share. Net loss attributable to common shareholders in the third quarter of 2011 was $16.4 million, or ($0.40) per diluted share.

Operating income (1) was $23.8 million in the third quarter of 2012, or $0.62 per diluted share, compared to an operating loss of $15.3 million in the third quarter of 2011, or ($0.38) per diluted share. The operating loss in the third quarter of 2011 included losses from Hurricane Irene which were estimated at $60.1 million ($39.1 million after-tax, or $0.96 per diluted share) in the third quarter 2011 and revised to $45.0 million ($29.2 million after tax, or $0.72 per diluted share) in the fourth quarter of 2011. The Company experienced $15.1 million of favorable development from Hurricane Irene claims in the fourth quarter of 2011.

During the quarter, Tower settled its previously disclosed litigation with Munich Reinsurance America, Inc. (“Munich”) for $2.9 million after-tax ($0.08 per share), which is included as a charge against its third quarter 2012 operating results. This settlement pertained to business that was sourced prior to 2001 from Tower’s Insurance Services segment.

Highlights (all figures compare third quarter 2012 results to the results for the same period in 2011 except as noted):

Michael H. Lee, President and Chief Executive Officer of Tower Group, Inc., said, “During the quarter, we continued to see positive trends in our business in terms of growth and underwriting profitability as well as improving market conditions. Our growth during the quarter was driven by our organic initiatives which are focused on expanding our products, improving existing business units and creating new business units and improving the various operating processes associated with generating growth. We saw continued strength in our assumed reinsurance business and are beginning to see significant demand for customized product solutions with key distribution sources. In addition to seeing robust growth opportunities, we made significant progress in non-renewing unprofitable business and continued to drive rate increases across all business units. Because of this, we are confident about the profitability of our on-going business and remain well positioned to take advantage of the improving market conditions. We are also progressing well with our proposed merger transaction with the Bermuda reinsurance business of Canopius. Our fourth quarter operating results will be adversely affected by Superstorm Sandy, which will easily cause the largest catastrophic event in our history. Our sympathies go out to those who have been severely impacted by this event, including our policyholders, agents and employees situated in the affected areas. While it is premature to estimate the full extent of our insured losses, we are confident that our capital position for the year will not be materially impaired based on the claims reporting pattern thus far, our underwriting profile and robust reinsurance program, which was substantially strengthened after Hurricane Irene last year. Despite the obvious challenges arising from this event, we are proud of the performance and the dedication of our staff, who have been working around the clock to service our customers and agents.”

On October 29, 2012, Superstorm Sandy made landfall in New Jersey and caused significant property damages which are still being determined. Tower has exposure to Superstorm Sandy through its direct insurance operations and its reinsurance assumed and ceded businesses. Losses from its insurance operations are covered by reinsurance after certain loss thresholds are incurred by the company. For Tower’s companies, excluding the reciprocal exchanges, losses incurred in excess of $75 million are ceded to Tower’s reinsurance program up to a gross loss of $150 million. Tower also maintains reinsurance for losses in excess of $150 million to $925 million; in these reinsured programs, Tower retains 30% of the losses between $150 million and $225 million. Tower expects its direct insurance losses to be contained within the first layer of its reinsurance program based on currently available information. Tower expects its pre-tax net loss from its direct insurance business to be between $90 million and $95 million pre-tax including reinstatement premiums. Tower’s assumed reinsurance business expects its losses to be between $15 million and $20 million pre-tax, based on its evaluation of currently available information. Tower also expects to recover $10 million if industry losses exceed $10 billion and an additional $10 million if industry losses exceed $15 billion through industry loss warranties that its ceded reinsurance business put in place in July 2012 to manage risk associated with its exposure in the Northeast. Tower believes that its alternative investments will not be materially affected by the losses associated with Superstorm Sandy. In aggregate, Tower’s current estimate of loss ranges from $55.3 million to $68.3 million, after-tax, based on its estimate of an industry loss between $10 billion and $15 billion. Tower expects that the reciprocal exchanges will have a net loss between $6.2 million and $7.5 million, after-tax, but such loss will not be included in Net Income Available to Tower Shareholders.

Financial Summary ($ in thousands, except per share data):

Financial Summary ($ in thousands, except per share data):

Reconciliation of non-GAAP financial measures ($ in thousands, except per share data):

Third Quarter 2012 Highlights

Consolidated

Gross premiums written and managed decreased to $484.8 million in the third quarter, 6.6% lower than in the third quarter of 2011. The decrease in the three months ended September 30, 2012 is primarily attributable to the non-renewal of one program that generated $51.7 million of gross written premium in the third quarter in 2011. The third quarter 2011 also included $23.3 million of premium from an assumed reinsurance treaty that was commuted in the fourth quarter 2011. Excluding these two actions, gross premiums written and managed increased by 8.2%. Policies in-force decreased by 0.8% as of September 30, 2012, compared to September 30, 2011, without programs. For the three months ended September 30, 2012, premiums on renewed Commercial Insurance business excluding programs increased 4.0% and premiums on renewed Personal Insurance business increased 4.5%, resulting in an overall premium increase on renewal business of 4.3%. During the same time period, our Commercial Insurance business renewal retention rate excluding programs was 83.7% and our Personal Insurance business renewal retention rate was 88.9%, resulting in an overall retention rate of 88.0%.

Total revenues increased 4.3% to $474.9 million in the third quarter of 2012 as compared to $455.3 million in the prior year’s third quarter. The growth was primarily due to increased net premiums earned. Net premiums earned represented 90.7% of total revenues for the three months ended September 30, 2012 compared to 90.8% for 2011.

Net investment income was flat at $31.4 million. The tax equivalent book yield on our investment portfolio, excluding the reciprocal exchanges, was 4.6% at September 30, 2012 compared to 4.5% at September 30, 2011. Net realized investment gains were $1.1 million for the quarter ended September 30, 2012 compared to gains of $0.2 million in the same period last year. Total commission and fee income increased 14.0% to $11.6 million in the third quarter of 2012 compared to $10.2 million in the third quarter of 2011.

The net loss ratio was 59.5% for the three months ended September 30, 2012 compared to 75.0% for the same period in 2011. (Excluding the business that we manage on behalf of the reciprocal exchanges, the net loss ratio was 60.8% for the third quarter of 2012 compared to 77.6% for the third quarter of 2011.) Included in the third quarter loss ratio were 12.5 points associated with

Hurricane Irene (12.3 points excluding the business that we manage on behalf of the reciprocal exchanges). Our net expense ratio was 36.5% for the three months ended September 30, 2012 compared to 34.9% for the same period in 2011. (Excluding the business that we manage on behalf of the reciprocal exchanges, the net expense ratio was 35.5% for the third quarter of 2012 compared to 34.4% for the third quarter of 2011.) The increase in the three months ended September 30, 2012 is primarily due to the assumed reinsurance business which has a higher commission ratio than other lines of business and an increase in the OUE ratio as a result of ongoing efforts to build-out the information technology infrastructure to support policy administration and claims processing needs. Acquisition-related transaction costs for the three and nine months ended September 30, 2012 were $2.7 million and $4.7 million, respectively, primarily attributed to the acquisition of our equity interest in Canopius Group and expenses associated with our recently announced proposed merger. These costs were negligible for the same periods in 2011.

Excluding the reciprocal exchanges, for the three months ended September 30, 2012, Tower’s effective tax rate was 27.1% in the third quarter 2012 compared to 31.6% in the same period in the prior year. Interest expense decreased by $0.4 million for the three months ended September 30, 2012, compared to the same period in 2011.

Additional Highlights and Disclosures

Dividend Declaration

Tower’s Board of Directors approved a quarterly dividend on November 6, 2012, of 18.75 cents per share payable on December 21, 2012, to stockholders of record as of December 10, 2012.

Guidance

Tower expects full year 2013 operating earnings per share to be in a range of $2.85 to $3.05 excluding any benefits of the proposed merger transaction.

Notes on Non-GAAP Financial Measures

(1) Operating income (loss) excludes realized gains and losses, acquisition-related transaction costs and the results of the reciprocal business, net of tax. Operating income is a common measurement for property and casualty insurance companies. We believe this presentation enhances the understanding of our results of operations by highlighting the underlying profitability of our insurance business. Additionally, these measures are a key internal management performance standard. Operating earnings (loss) per share is operating income (loss) divided by diluted weighted average shares outstanding. Operating return on equity is annualized operating income (loss) divided by average common stockholders’ equity.

Conference Call

Tower will host a conference call and webcast to discuss these results on November 8, 2012 at 9:00 a.m. ET. This conference call will be broadcast live over the Internet. To access a listen-only webcast over the Internet, please visit the Investor Information section of Tower Group, Inc.’s website, www.twrgrp.com, or use this link: http://investor.twrgrp.com/events.cfm

Please access the website at least 15 minutes prior to the call to register and to download any necessary audio software. If you are unable to participate during the live conference call, a webcast will be archived in the Investor Information section of Tower Group, Inc.’s website at www.twrgrp.com.

About Tower Group, Inc.

Tower Group, Inc. offers diversified property and casualty insurance products and services through its operating subsidiaries.

Our Commercial Insurance Segment offers a broad range of commercial lines property and casualty insurance products to small to mid-sized businesses distributed through a network of retail, wholesale and program underwriting agents on both an admitted and non-admitted basis. This segment also includes reinsurance solutions provided primarily to small insurance companies;

Our Personal Insurance Segment offers a broad range of personal lines property and casualty insurance products to individuals distributed through a network of retail and wholesale agents; and

Our Insurance Services Segment provides underwriting, claims and reinsurance brokerage services to insurance companies.

Cautionary Note Regarding Forward-Looking Statements

The Private Securities Litigation Reform Act of 1995 provides a “safe harbor” for forward-looking statements. This press release and any other written or oral statements made by or on behalf of Tower may include forward-looking statements that reflect Tower’s current views with respect to future events and financial performance. All statements other than statements of historical fact included in this press release are forward-looking statements. Forward-looking statements can generally be identified by the use of forward-looking terminology such as “may,” “will,” “plan,” “expect,” “project,” “intend,” “estimate,” “anticipate,” “believe” and “continue” or their negative or variations or similar terminology. All forward-looking statements address matters that involve risks and uncertainties. Accordingly, there are or will be important factors that could cause the actual results of Tower to differ materially from those indicated in these statements. Please refer to Tower’s filings with the SEC, including among others Tower’s Annual Report on Form 10-K for the year ended December 31, 2011 and subsequent filings on Form 10-Q, for a description of the important factors that could cause the actual results of Tower to differ materially from those indicated in these statements. Forward-looking statements speak

only as of the date on which they are made, and Tower undertakes no obligation to update publicly or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

For more information, visit Tower’s website at http://www.twrgrp.com/

Contact Information:

Bill Hitselberger

Executive Vice President and Chief Financial Officer

Tower Group, Inc.

212-655-2110

bhitselberger@twrgrp.com

Commercial Insurance & Personal Insurance Combined

($ in thousands)

(Unaudited)

Commercial Insurance Segment Information

($ in thousands)

(Unaudited)

Personal Insurance Segment Information

($ in thousands)

(Unaudited)