Half Year 2023 Earnings Press Release

Exhibit 99.1

PRESS

RELEASE

Aspen Reports Strong Financial Results for the First Six Months of 2023

• Net income increased by 352% to $219 million (June 30, 2022: $48 million)
• Operating income* increased by 47% to $191 million (June 30, 2022: $130 million)
• Annualized operating retuon average equity* of 22% (June 30, 2022: 14%)
• Underwriting income increased by 33% to $208 million (June 30, 2022: $157 million), resulting in a
  combined ratio of 83.8% (June 30, 2022: 88.2%)
• Aspen Capital Markets' total fee income increased by 28% to $61 million (June 30, 2022: $47 million)
• Net investment income increased by 46% to $129 million (June 30, 2022: $89 million)

Hamilton, Bermuda, August 22, 2023 - Aspen Insurance Holdings Limited ("Aspen") today reported results for the six months ended June 30, 2023.

CEO statement

We are pleased to report a strong set of results for the first half of 2023, which saw our operating income* and net income continue to increase, by 47% to $191 million and by 352% to $219 million, respectively.

We are particularly encouraged to report another period of improved underwriting performance, with our reported combined ratio improving to 83.8% and underwriting income of $208 million. This result reflects the sustained impact of our highly disciplined approach and the benefits of the well-diversified portfolio we have deliberately constructed.

Our gross written premium was $2,125 million, which was slightly lower compared to the same period last year. This is the result of our continuing effort to use current favorable trading conditions to further reduce exposure and manage volatility, while holding our discipline in certain classes where pricing and terms do not meet our retuobjectives, as demonstrated by our improved underwriting income. While broadly trading conditions are strong, resulting in a 12% rate increase across our whole portfolio, our focus remains on rate adequacy, terms and conditions rather than just rate change. Growing and maintaining our profitability as conditions shift will always be our first priority.

Positive performance across Insurance, Reinsurance and Investments

Our diverse portfolio across our two underwriting segments, Insurance and Reinsurance, allows us to flexibly manage our business. Our underwriting income was well balanced across these two segments and their positive performance was further strengthened by continued expense discipline across the Group, with general and administrative expenses decreasing by 9% to $169 million, notwithstanding inflationary pressures on our cost base.

• Non-GAAPfinancial measures are used throughout this release, such as Operating Income. For additional information and reconciliation of non-GAAP financial measures, refer to the end of this press release. Refer to "Cautionary Statement Regarding Forward-Looking Statements" at the end of this press release.

Key financial highlights

• Gross written premiums of $2,125 million in the six months ended June 30, 2023, a decrease of 10% compared to $2,351 million in the six months ended June 30, 2022, consistent with management's strategy to optimize portfolio, reduce exposure and manage volatility, partially offset by rate increases.
• Net written premiums of $1,351 million in the six months ended June 30, 2023, a decrease of 10% compared to $1,506 million in the six months ended June 30, 2022. Premiums ceded to reinsurers as a percentage of gross written premium in the six months ended June 30, 2023, was 37% compared with 36% in the six months ended June 30, 2022.
• Underwriting income of $208 million (adjusted underwriting income* of $196 million) in the six months ended June 30, 2023, compared to an underwriting income of $157 million (adjusted underwriting income of $131 million) in the six months ended June 30, 2022, resulting in a combined ratio of 83.8% (adjusted combined ratio of 84.8%) for the six months ended June 30, 2023, compared to 88.2% (adjusted combined ratio of 90.2%) for the six months ended June 30, 2022.
• Losses and loss adjustment expenses include:
• • Current accident year losses, excluding catastrophe losses, of $670 million, or 52.1 percentage points on the combined ratio, in the six months ended June 30, 2023, compared to $682 million, or 51.4 percentage points on the combined ratio in the six months ended June 30, 2022.
  • Catastrophe losses of $53 million, or 4.1 percentage points on the combined ratio, for the six months ended June 30, 2023, included losses associated with floods in New Zealand, Cyclone Gabrielle, wildfires in Chile and other weather-related events. Catastrophe losses of $93 million, or 7 percentage points on the combined ratio, for the six months ended June 30, 2022, included losses associated with floods in Australia and South Africa, the Russia/Ukraine war and other weather-related events.
  • Net favorable development on prior year loss reserves of $6 million, or 0.5 percentage points on the combined ratio, in the six months ended June 30, 2023, compared with net favorable development of $7 million, or 0.6 percentage points on the combined ratio in the six months ended June 30, 2022.
• Acquisition costs as a percentage of net earned premium improved from 16% in 2022 to 15% in 2023. This is primarily driven by an increase in fee income derived from Aspen Capital Markets, which increased to $61 million in the six months ended June 30, 2023, compared to $47 million in the six months ended June 30, 2022. Fee income from Aspen Capital Market's activities is primarily allocated to the ceded line of business and serves to reduce acquisition expenses for that business.
• General and administrative expenses decreased to $169 million, representing 13 percentage points on the combined ratio, in the six months ended June 30, 2023, compared with $187 million, and 14 percentage points on the combined ratio, in the six months ended June 30, 2022. The reduction in general and administrative expenses was primarily driven by the favorable year over year foreign exchange rates, coupled with various cost saving initiatives.
• Net investment income of $129 million in the six months ended June 30, 2023, compared to $89 million in the six months ended June 30, 2022.
• Interest expense increased to $43 million in the six months ended June 30, 2023, compared with interest expense of $9 million in the six months ended June 30, 2022. This increase is primarily driven by $36 million of interest on the funds withheld related to the loss portfolio transfer ("LPT") contract.
• Tax expense increased to $36 million in the six months ended June 30, 2023, compared with tax expense of $5 million in the six months ended June 30, 2022. The increase in tax expense was driven by higher pre-tax profits in our taxable jurisdictions compared to the prior year. The 2022 tax charge also benefited from the utilization of brought forward net operating losses that had a full valuation allowance recorded against U.S. profits.

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• Net income includes net realized and unrealized investment gains of $18 million in the six months ended June 30, 2023, compared to losses of $126 million in the six months ended June 30, 2022. The change in net realized and unrealized investment gains and losses is a result of mark to market valuations, predominantly driven by credit spread reduction in our government, corporate bond and structured credit portfolio and lower allocations to rate sensitive asset classes.
• Book yield on the fixed income securities portfolio as at June 30, 2023, was 3.5% compared with 3.2% as at December 31, 2022.
• Annualized operating retuon average equity of 22% in the six months ended June 30, 2023, compared to 14% in the six months ended June 30, 2022.

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