The Navigators Group, Inc. “Insuring a World in Motion” CSFB Insurance Conference March 25, 2004

1. The Navigators Group, Inc.“Insuring a World in Motion”CSFB Insurance ConferenceMarch 25, 2004 Stanley A. Galanski, President & Chief Executive Officer Paul J. Malvasio, Executive Vice President & Chief Financial Officer

2. This presentation may contain “forward looking statements” as defined in the Private Securities Litigation Act of 1995. We cannot assure that results which we anticipate will be achieved, since results may differ materially because of known and unknown risks and uncertainties which we face. Please refer to Navigators’ most recent Form 10-K for a description of Navigators’ business and the important factors which may affect that business. Navigators undertakes no obligation to publicly update or revise any forward looking statement.

3. Navigators – Corporate Overview • Specialty Insurance Holding Company • Specialty niches include: • Marine, Energy • D&O, Professional Liability • Specialty Property/Casualty • Construction • Surety • Personal Umbrella • Insurance subsidiaries “A” rated by A.M. Best and S&P • Operations at Lloyd’s provide a global platform • Offices in major ports/insurance centers in the U.S. and U.K. • New York, Seattle, San Francisco/Oakland, Houston, Chicago • London, Manchester, Leeds, Basingstoke

4. Navigators – Investment Highlights • A global leader in marine insurance • Business founded through Navigators Agencies in 1974 • Lloyd’s presence through Syndicate 1221 acquired in 1998 • Complements US operations and provides global market access • Commitment to underwriting profit • World-class specialty underwriting teams • Emphasis on bottom-line results, not market share • Diversifying opportunistically into attractive new business lines • Specialty Property & Casualty and Professional Liability • Excellent market opportunities and producer support • Portfolio diversification for stronger earnings stream across market cycles • Operating from a strong and leveragable platform • Rated “A” by A.M. Best and Standard and Poor’s • Lloyd’s licenses provide access to major world markets • No legacy balance sheet issues • No debt

5. Deep, Experienced Underwriting Team • Senior underwriting management team has an average of approximately 29 years in the industry and 13 years at NAVG.

6. Navigators Agencies Marine & Energy 32% of 2003 GPW • Navigators has an 80% participation in marine insurance pool operated by Navigators Agencies in 2003 • Recognized leader in the U.S. Bluewater Hull and Liability lines • One of the largest marine portfolios in the U.S. market • Navigators U.K. Branch has become our largest regional marine office • Rate increases on renewal business of 13% in 2003 and 21% in the year 2002

7. 2002 U.S. Market Share ($ in thousands) Note: As reported by the AIMU.

8. Lloyd’s Marine & Energy 37% of 2003 GPW • Navigators Underwriting Agency, Ltd. manages Syndicate 1221 • Navigators provides 97.4% of Syndicate 1221’s gross capacity / $255mm for 2004 underwriting year compared to $200mm for 2003 • A Lloyd’s market leader in cargo and specie insurance • Millennium Consortium at Lloyd’s for construction/engineering risks • Expansion of Pennine operations positioned in three regional U.K. offices • Rate increase of 15% in 2003, after 26% rate increase in 2002

9. 2002 Lloyd’s Market Share (₤ in thousands) Source: Lloyd’s Market Association

10. Navigators Specialty 22% of 2003 GPW • Specialty P&C products are written on an admitted or surplus line basis • Since 1995 has underwritten general liability insurance for small general and artisan contractors, mostly in California • Acquired Anfield Insurance Services in 1999 • Specialty underwriting/claims expertise • Strategy to diversify by product line and geographically • Midwest branch operation since 2002 • Surety and personal umbrella products • Three newer initiatives generated approximately 20% of 2003 specialty gross written premium • Rate increase of 49% in 2003, after 30% rate increase in 2004 for contractors liability business

11. Navigators Pro 9% of 2003 GPW • Introduced D&O liability insurance in late 2001 with team of experienced professionals • Traditionally very profitable niche business in P&C industry • Compelling market opportunity given recent shareholder lawsuits • Focus on privately held and small to mid-size public corporations • In late 2002, introduced lawyers professional liability and other miscellaneous professional liability coverages • Complementary products for D&O clients include: • Fiduciary liability • Employment practices liability • Crime insurance

12. Growth and Portfolio Diversification Gross Premium Written by Segment($ in millions) $606.5 CAGR: 47.6% 8.7% 21.7% 37.2% 32.4% $447.8 5.2% 26.3% 28.5% 40.0% $278.2 0.3% 21.6% 39.3% 38.9%

13. Underwriting Culture Focuses on Profitability Normalized Combined Ratio (1)Excludes 2.7% for World Trade Center losses of $4.5 million recorded in 2001 (2) Excludes 11.7% for A&E losses of $31.6 million recorded in 2003

14. Prudent Reserving Practices ($ in millions) $374.2 48.9% 51.1% $264.6 58.7% 41.3% $202.8 46.2% 53.8%

15. High Quality Investment Portfolio At December 31, 2003 • Total Portfolio Size: $694 million • Fixed Maturities and Cash: 98% of portfolio • Average AA rating • Duration of approximately 3.7 years • Average yield of 3.8% for 2003 • Equity Securities: 2% of portfolio 13% 2% 32% 20% 13% 20%

16. Net Income and Book Value Growth Per share data (1)Adjusted for World Trade Center losses of $4.5 million or $0.53 per share (2) Adjusted for 2003 fourth quarter asbestos losses of $31.5 million or $2.14 per share

17. Why Navigators Now? • Global leader in marine insurance • Diversification strategy is on target • Experienced management team • Intellectual capital / specialty expertise • Commitment to underwriting profit • Proven track record • Operating from a strong and leveragable platform

18. “Insuring a World in Motion”