Corporate Structure and Nature of Operations; Basis of Presentation	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Corporate Structure and Nature of Operations; Basis of Presentation	Corporate Structure and Nature of Operations; Basis of Presentation Corporate Structure and Nature of Operations Eastern Bankshares, Inc., a Massachusetts corporation (the “Company”), is a bank holding company. Through its wholly-owned subsidiary, Eastern Bank (the “Bank”), the Company provides a variety of banking services and trust and investment services, through its full-service bank branches, located primarily in eastern Massachusetts, southern and coastal New Hampshire, and Rhode Island. The activities of the Company are subject to the regulatory supervision of the Board of Governors of the Federal Reserve System (“Federal Reserve”). The activities of the Bank are subject to the regulatory supervision of the Massachusetts Commissioner of Banks, the Federal Deposit Insurance Corporation (“FDIC”) and the Consumer Financial Protection Bureau (“CFPB”). The Company and the activities of the Bank and its subsidiaries are also subject to various Massachusetts, New Hampshire and Rhode Island business, banking and trust-related regulations. Basis of Presentation The Company’s Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and its Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) as well as the rules and interpretive releases of the U.S. Securities and Exchange Commission (“SEC”) under the authority of federal securities laws. The Consolidated Financial Statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which it holds a controlling financial interest through being the primary beneficiary or through holding a majority of the voting interest. All intercompany accounts and transactions have been eliminated in consolidation. Certain previously reported amounts have been reclassified to conform to the current period’s presentation which includes: •reclassification of certain mortgage banking income accounts previously included in “(losses) gains on mortgage loans held for sale, net” and in “other noninterest income” to a new financial statement line item titled “mortgage banking income (loss).” •combination of certain non-operating income accounts previously included in “other noninterest income” into a new financial statement line item titled “other non-operating loss.” The accompanying Consolidated Balance Sheet as of March 31, 2026, the Consolidated Statements of Income and Comprehensive Income and of Changes in Shareholders’ Equity for the three months ended March 31, 2026 and 2025 and Statements of Cash Flows for the three months ended March 31, 2026 and 2025 are unaudited. The Consolidated Balance Sheet as of December 31, 2025 was derived from the Audited Consolidated Financial Statements as of that date. The interim Consolidated Financial Statements and the accompanying notes should be read in conjunction with the annual Consolidated Financial Statements and the accompanying notes contained within the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (“2025 Form 10-K”), as filed with the SEC. In the opinion of management, the Company’s Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim period, or any future year or period.

Eastern Bankshares, Inc., a Massachusetts corporation (the “Company”), is a bank holding company. Through its wholly-owned subsidiary, Eastern Bank (the “Bank”), the Company provides a variety of banking services and trust and investment services, through its full-service bank branches, located primarily in eastern Massachusetts, southern and coastal New Hampshire, and Rhode Island.

The activities of the Company are subject to the regulatory supervision of the Board of Governors of the Federal Reserve System (“Federal Reserve”). The activities of the Bank are subject to the regulatory supervision of the Massachusetts Commissioner of Banks, the Federal Deposit Insurance Corporation (“FDIC”) and the Consumer Financial Protection Bureau (“CFPB”). The Company and the activities of the Bank and its subsidiaries are also subject to various Massachusetts, New Hampshire and Rhode Island business, banking and trust-related regulations.

The Company’s Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and its Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) as well as the rules and interpretive releases of the U.S. Securities and Exchange Commission (“SEC”) under the authority of federal securities laws.

The Consolidated Financial Statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which it holds a controlling financial interest through being the primary beneficiary or through holding a majority of the voting interest. All intercompany accounts and transactions have been eliminated in consolidation.

•reclassification of certain mortgage banking income accounts previously included in “(losses) gains on mortgage loans held for sale, net” and in “other noninterest income” to a new financial statement line item titled “mortgage banking income (loss).”

The accompanying Consolidated Balance Sheet as of March 31, 2026, the Consolidated Statements of Income and Comprehensive Income and of Changes in Shareholders’ Equity for the three months ended March 31, 2026 and 2025 and Statements of Cash Flows for the three months ended March 31, 2026 and 2025 are unaudited. The Consolidated Balance Sheet as of December 31, 2025 was derived from the Audited Consolidated Financial Statements as of that date. The interim Consolidated Financial Statements and the accompanying notes should be read in conjunction with the annual Consolidated Financial Statements and the accompanying notes contained within the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (“2025 Form 10-K”), as filed with the SEC. In the opinion of management, the Company’s Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim period, or any future year or period.