UIL (UIL) 8-K Important Note to Investors

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Shields Transmission Seminar

Wellington Shields & Co.

Transmission Seminar

January 11, 2011

EXHIBIT 99.1

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Important Note to Investors

Richard Peters

Associate Vice President, Transmission

Safe Harbor Provision

Certain statements contained herein, regarding matters that are not historical facts, are forward-looking statements (as defined in the
Private Securities Litigation Reform Act of 1995). These include statements regarding management’s intentions, plans, beliefs,
expectations or forecasts for the future. Such forward-looking statements are based on UIL Holdings’ expectations and involve risks and
uncertainties; consequently, actual results may differ materially from those expressed or implied in the statements. Such risks and
uncertainties include, but are not limited to, general economic conditions, legislative and regulatory changes, changes in demand for
electricity, gas and other products and services, unanticipated weather conditions, changes in accounting principles, policies or
guidelines, and other economic, competitive, governmental, and technological factors affecting the operations, markets, products and
services of UIL Holdings’ subsidiaries, The United Illuminating Company, The Southern Connecticut Gas Company, Connecticut
Natural Gas Corporation and The Berkshire Gas Company. Such risks and uncertainties with respect to UIL Holdings’ recent acquisition
of The Southern Connecticut Gas Company, Connecticut Natural Gas Corporation and The Berkshire Gas Company include, but are not
limited to, the possibility that the expected benefits will not be realized, or will not be realized within the expected time period. The
foregoing and other factors are discussed and should be reviewed in UIL Holdings’ most recent Annual Report on Form 10-K and other
subsequent periodic filings with the Securities and Exchange Commission. Forward-looking statements included herein speak only as of
the date hereof and UIL Holdings undertakes no obligation to revise or update such statements to reflect events or circumstances after the
date hereof or to reflect the occurrence of unanticipated events or circumstances.

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Today’s Topics

nUIL Corporate Structure, Service Areas

nUIL-Wide Projected CapEx

nNear-Term

nTen-Year

nUIL-Wide Projected Rate Base

nTransmission Highlights

nProjected Capital Program

nExamples of Current Reliability Upgrades

nNEEWS Investment

nRegion-Wide RPS Obligations

nRenewable-Enabling Transmission

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UIL - Corporate Structure, Service Areas

§Service territory: 335 sq
miles

§~324,000 customers

§1,066 employees

§Allowed Distribution ROE
of 8.75%

§Allowed ’09 Transmission
ROE (composite) of 12.52%

§50% interest in GenConn
Energy LLC

The United Illuminating
Company (UI)

Note:(1) Includes 10 basis point penalty reduction.Previously authorized 10.0% in effect pending resolution of rate case appeals.

UIL Holdings
Corporation

Service Area Key

SCG

CNG

UI

Berkshire

Overlapping Territory

§Service territory: 716 sq
miles - Greater Hartford-
New Britain & Greenwich

§~158,000 customers

§341 employees

§2,011 miles of mains with
~124,000 services

§2009ratecaseallowed
ROEof9.31% (1)

Connecticut Natural Gas
(CNG)

§Service territory: 738 sq
miles in Western MA
including Pittsfield and
North Adams

§~35,000 customers

§127 employees

§738 miles of mains

§Allowed ROE of 10.50%

Berkshire Gas Company
(Berkshire)

§Service territory: 512 sq
miles from Westport, CT to
Old Saybrook, CT

§~173,000 customers

§324 employees

§2,269 miles of mains with
~131,000 services

Southern Connecticut Gas
(SCG)

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Total CapEx ($M)

2011P - 2015P

Electric Distribution

$695

Electric Transmission

314

Gas Distribution (1)

GenConn

316

63

UIL (Total)

$1,389

UIL Near-Term Regulated Capital Investment*

($M)

Identified projects with clear need.

Electric Distribution

GenConn

Electric Transmission

Gas Distribution

Notes:(1) Gas Distribution projected CapEx provided by Iberdrola, USA prior to closing on the acquisition.*Amounts may not add due to rounding.

20%

27%

53%

18%

16%

48%

24%

17%

59%

27%

20%

53%

25%

27%

48%

18%

23%

34%

43%

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Notes: *Gas Distribution projected capex provided by Iberdrola, USA prior to closing on the acquisition.** Equity investment - Devon plant now operating,
Middletown expected operation June 2011.Amounts may not add due to rounding.

Identified projects with clear need and regulatory support.

($ in millions)

Base 10-yr CapEx by Business:

UIL-Wide Base 10-yr CapEx Forecast

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Near-Term Average Rate Base Profile

48%

40%

12%

29%

21%

5%

35%

3%

41%

Attractive rate base growth even with a declining CTA balance.

1%

23%

38%

38%

39%

45%

21%

38%

23%

37%

40%

23%

Notes: *Gas Distribution rate base projections provided by Iberdrola, USA prior to closing on the acquisition.Amounts may not add due to rounding.

Electric Distribution

CTA

Gas Distribution*

Electric Transmission

UI’s 50% Share ($M):2010P2011P2012P2013P2014P2015P

Avg. GenConn RB Equivalent:$ 51$ 147$ 185$ 175$ 166$ 158

Avg. Gen Conn Equity “Rate Base”$ 25$74$92$88$83$79

Rate Base (Excluding GenConn Equity Investments):

GenConn Equity Investments:

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Base 10-Yr. Txm Capital Investment Program

2010P - 2019P:$593M

Aging Infrastructure
$265M

Capacity-Driven

$121M

Standards Compliance, Other
$207M

Notes:Amounts may not add due to rounding.*Expected in-service year (subject to change).

A well-balanced portfolio of high-probability projects.

Examples:

nPequonnock 115 kV Substation Fault Duty
Mitigation (2015*)

nNaugatuck Valley Reliability (2014*)

nDevon Tie Switching Station BPS Upgrades
(2011*)

Examples:

nNew Broadway II 115/13.8 kV Substation
(placed in-service 2010)

nNew Union Avenue 115/26.4 kV Substation
(2012*)

nNew Shelton 115/13.8 kV Substation (2016*)

Examples:

nGrand Avenue 115 kV
Switching Station Rebuild
(2012*)

nEast Shore 115 kV
Substation Upgrades (2011-
2013*)

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Grand Avenue 115 kV Switching
Station Rebuild

Pequonnock 115 kV Substation
Fault Duty Mitigation

New Union Avenue 115/ 26.4 kV
Substation

East Shore 115 kVSubstation Upgrades

§Addresses short circuit capability issues and
aged/obsolete infrastructure

§Under construction

§Planned in-service
2012

~ $60M*

§Circuit breakers are nearing their capabilities to
safely interrupt high short circuit current

§Alternatives under
evaluation

§Planned in-service
2015

~ $60M*

§In engineering

§Planned in-service
2012

~ $15M*

§Addresses infrastructure condition, maintenance
short circuit capability concerns

§Phased upgrades,
in engineering and
construction

§Planned in-service
2011-2013

~ $25M*

Notes:*Dollars shown are rounded/approximate expected total project CapEx (generally including both spend to date and future expected spend); excluding AFUDC.

Examples of Current Transmission
Reliability Upgrades

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UI Transmission - NEEWS Investment

UI Participation in CL&P Project:

nUI’s portion of investment: greater of
$60M or 8.4% of CL&P’s costs for the
CT portions …

n8.4% currently estimated at
approximately $69M (increased from
original estimate of $60M).

nFirst deposit made in December 2010.

UI’s anticipated investment increased from $60M to $69M.

Refreshed UI Investment Amounts and Timeline:

($ in millions)

Potential UI Investment*

2010P

2011P

2012P

2013P

2014P

2015P

2016P

Total

Current Projection

7

$

3

$

9

$

8

$

12

$

23

$

7

$

69

$

Previous Projection**

-

$

10

$

9

$

8

$

12

$

23

$

7

$

69

$

Difference

* Based on NU's latest projection of UI's Investment in CL&P's portion of the NEEWS Projects.

** Presentedon 12/3/10

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Notes:* RPS = Renewable Portfolio Standard. **From ISO-NE Presentation dated 5/15/09 - driven by 2008 data.***From ISO-NE Presentation dated 5/25/10 -
“existing” includes RPS obligations through 2009.Total RPS Requirement excludes Vermont renewables, combined heat & power, and energy efficiency obligations.

Region-Wide
Compliance Gap

(v. “existing” renewable resources**)

forecasted/estimated at

~ 18,000GWh

Region-Wide RPS Obligation thru 2020:

See Appendix for summary of CT’s RPS Requirements

nUnlikely to be
satisfied by
renewables currently
in the ISO-NE queue.

nWill require
significant additional
transmission.

Satisfaction will likely require significant new transmission in the region.

Region-Wide RPS* Obligations

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Renewable-Enabling Transmission

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Collaborative effort: UI, NU, NSTAR, and NGrid …

to research / identify the most economical means of satisfying future RPS obligations

Significant Region-Wide Need:

nRPS requirement > 3x current
available renewables*.

nCT requirement** is > UI’s entire load.

nGap will be filled by renewables
remote from load.

N.E. Governors’ Blueprint:

nSignificant transmission build-out
indicated.

nPotential $7 to $10B range - could be
higher or lower to satisfy a 4,000 to
12,000 MW need.

nCost to New England likely much less
than Midwestern wind.

Potential Solutions Under Study

nNeed will likely be satisfied by a portfolio
of projects.

nOne promising example is shown below.

Notes:*From ISO-NE Presentation dated 5/15/09 - driven by 2008 data.**Refer to Appendix for summary of CT RPS requirements.

Vast majority of
potential onshore
renewables (wind)

are in northern NE

North-South Interface:

80% of NE electric
load is below this line

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Q&A

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Appendices

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›Connecticut Department of Public Utility Control (DPUC)

›Distribution currently operating under 2 year rate plan with full revenue decoupling pilot*

›Allowed ROE of 8.75%, based on a capital structure of 50.0% equity

›Federal Energy Regulatory Commission (FERC)

›Transmission trued up on an annual basis to allowed composite ROE based on FERC approved formula rate

›2010 composite ROE of approximately 12.4%-12.5%, based on a capital structure of 50.0% equity

›DPUC Contracts for Differences with CL&P (subsidiary of Northeast Utilities) and cost sharing agreement (80% CL&P /
20% UI)

›Allowed ROE has a lifetime floor of 9.75% based on a capital structure of 50.0% equity

›Connecticut Department of Public Utility Control (DPUC)

›2009 Rate Case decision is under appeal and has been stayed pending determination of the appeal

›Currently operating under old rates with embedded overearnings credit - new rates per rate case virtually the same as old
rates currently in place

›Allowed ROE of 9.26%*, based on a capital structure of 52.0% equity

›Massachusetts Department of Public Utilities (DPU)

›10 year constructive rate plan expiring 1/31/12

›Rates adjusted annually based on inflation and other factors

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Regulatory Overview

Distribution

Transmission

Notes:(1)The revenue decoupling mechanism was allowed to continue until the Department issues its final ruling in 2011 on the evaluation of this adjustment mechanism.*Previously
authorized 10.0% in effect pending resolution of rate case appeals.

›Connecticut Department of Public Utility Control (DPUC)

›2009 Rate Case decision is under appeal and has been stayed pending determination of the appeal

›Currently operating under old rates with embedded overearnings credit - new rates per rate case virtually the same as old
rates currently in place

›Allowed ROE of 9.31%*, based on a capital structure of 52.5% equity

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Connecticut RPS Requirements

(Percentage of Retail Load)

Class I resources include energy derived from solar, wind, fuel cell, methane gas from landfills, ocean thermal, wave,
tidal, run-of-river hydropower (<5MW, began operation after July 1, 2003), sustainable biomass (NOx emission <0.075
lbs/MMBtu of heat input)

Class II resources include other biomass (NOx emission <0.2 lbs/MMBtu of heat input, began operation before July 1,
1998), small run-of-river hydroelectric (<5MW, began operation before July 1, 2003) and municipal solid waste trash-to-
energy facilities.

Class III include customer-sited combined heat and power (with operating efficiency >50% of facilities installed after
January 1, 2006), waste heat recovery systems (installed on or after April 1, 2007), electricity savings from conservation
and load management programs (began on or after January 1, 2006)

CT RPS Requirements