AUBURN NATIONAL BANCORPORATION, INC

In addition to results presented in accordance with U.S. generally accepted

accounting principles (GAAP), this quarterly

report on Form 10-Q includes certain designated net interest income

amounts presented on a tax-equivalent basis, a non-

GAAP financial measure, including the presentation and calculation

of our net interest margin and efficiency ratio.

In the

first quarter of 2026, we changed the presentation of net interest income on a tax-equivalent

basis to account for tax-exempt

Prior period amounts have been revised herein to conform with the current period

presentation. These changes had no effect on the presentation

of GAAP net interest income in current or prior periods.

The Company believes the presentation of net interest income on a tax-equivalent

basis provides comparability of net

interest income from both taxable and tax-exempt sources and facilitates comparability

within the industry. Although

the

Company believes these non-GAAP financial measures enhance investors’

understanding of its business and performance,

these non-GAAP financial measures should not be considered an alternative

to GAAP.

The reconciliations

of these non-

GAAP financial measures to their most directly comparable GAAP financial measures

are presented below.

Second

First

Fourth

Third

Second

Quarter

Quarter

Quarter

Quarter

Quarter

$

7,888

7,733

7,713

7,572

7,344

Tax-equivalent adjustment

Net interest income (Tax

-equivalent)

$

7,995

7,832

7,780

7,641

7,411

$

15,621

14,389

Tax-equivalent adjustment

N

et interest income (Tax-equivalent)

$

15,827

14,523

Table 2

– Selected Quarterly Financial Data