Chubb Ltd. reported lower profit in the first quarter of 2016 but said it expects to see higher-than-expected savings from the integration of the former Chubb Corp. and Ace Ltd. operations as it prepares to navigate an increasingly competitive environment.

The Zurich-based insurer’s net income declined 35.5% in the first quarter of 2016 to $439 million from the same period of 2015, according to the company’s first-quarter earnings report released Wednesday afternoon. The insurer’s consolidated net premiums written rose 47.1% to $6 billion, compared with the first quarter of 2015, according to the report, while one-time losses related to the merger of Ace and Chubb in January came in at $106 million.

Chubb’s property/casualty combined ratio for the quarter was 90%, up from 88.4% in the prior-year quarter.

“Our earnings for the quarter were very good while our premium revenue results were somewhat impacted by market conditions, foreign exchange and the merger,” Chairman and Chief Executive Officer Evan Greenberg said during the company’s earning conference call on Thursday.

In 2016 and 2017, the company plans “to shed or shrink net written premiums in certain portfolios simply because we cannot earn adequate underwriting returns or because we want to reduce net cat-related exposures,” he said. “These actions will benefit both the returns and the risk-reward profile of the company.

Chubb closed “the largest P&C transaction ever done” during the first quarter and now expects savings of $750 million by fiscal year 2018, up from a previous projection of $650 million, Mr. Greenberg said.

The company is “seeing a really great response from agents, brokers and customers all over the world and in all regions of the U.S. about the new Chubb,” he said. “For brokers and large account clients, the size and quality of our balance sheet, our enhanced global capabilities, both service and product-related, our consistency and focus, in contrast to the problems they are experiencing with others, are all attracting more opportunity and our pipeline is building.”

However, Mr. Greenberg attributed a struggle to secure new business in North America in the first quarter to a competitive environment in January and the intense focus of employees on planning for, and the potential impact of, the integration of the two entities.

In addition, natural catastrophe losses were higher in the first quarter of 2016, with total pretax and after-tax catastrophe losses, including reinstatement premiums of $258 million and $204 million, respectively, compared with $51 million and $40 million, respectively, in the prior-year quarter according to the report.

Chubb demonstrated “very, very strong results in the quarter, with sustained underwriting profitability notwithstanding really, really high catastrophes,” said Meyer Shields, managing director at Keefe Bruyette & Woods Inc. in Baltimore. He also noted the company’s expectations for increased merger-related savings and increased investment income beginning in the latter half of 2016. “I think there are a lot of reasons to be optimistic in both the near term and longer term about the earnings power of the company.”

Going forward, it will be key to watch how Chubb’s strategy adds to the competitiveness of the industry and how much it benefits from competitors American International Group Inc. and Zurich Insurance Group Ltd. “trying to repair their own earnings,” he said.

Mr. Greenberg was asked during the call about the potential to siphon market share from Chubb’s competitors.

“It’s a double-edged sword, and you’ve got to be careful,” he said. “On one hand, when there is a wounded animal loose, be careful, stay out of the way. I don’t try to corner him. On the other hand, we represent a very attractive market, an alternative for large accounts seeking a deep balance sheet, great underwriting expertise, great reputation for service, global capability, a broad product offering and services.”