FIRST BUSEY CORP /NV/

This Quarterly Report contains certain financial information determined by methods other than in accordance with GAAP. Management uses these non-GAAP financial measures and non-GAAP ratios, together with the related GAAP financial measures, in analysis of Busey’s performance and in making business decisions, as well as for comparison to Busey’s peers. Busey believes the adjusted measures are useful for investors and management to understand the effects of certain non-core and non-recurring noninterest items and provide additional perspective on Busey’s performance over time.

Non-GAAP disclosures have inherent limitations and are not audited. They should not be considered in isolation or as a substitute for the results reported in accordance with GAAP, nor are they necessarily comparable to non-GAAP performance measures that may be presented by other companies. Tax effected numbers included in these non-GAAP disclosures are based on estimated federal income tax rates or effective tax rates as noted in the tables below.

The following tables present reconciliations between these non-GAAP measures and what management believes to be the most directly comparable GAAP financial measures.

First Busey Corporation(BUSE) | 2026 Q2 — 90

1. The Day 2 provision represents the initial provision for credit losses recorded in connection with the CrossFirst acquisition to establish an allowance on non-PCD loans and unfunded commitments and is reflected within the provision for credit losses line on the Statements of Income (Unaudited).

2. In the second quarter of 2025, Busey recorded an adjustment to the initial provision for unfunded commitments for CrossFirst acquisition-date balances based on revised estimates resulting from implementation of a new CECL model.

3. Tax benefits were calculated using tax rates of 25.0% and 26.5% for the six months ended June 30, 2026 and 2025, respectively. Tax benefits for quarterly periods were calculated as the year-to-date tax amounts less the tax reported for previous quarters during the year.

4. A deferred tax valuation adjustment was recorded in the first quarter of 2025 in connection with the CrossFirst acquisition and the expansion of Busey’s footprint into new states. Additionally, 2025 included a write-off of deferred tax assets related to non-deductible compensation and acquisition-related expenses. Deferred tax adjustments are reflected within the income taxes line on the Statements of Income (Unaudited).

First Busey Corporation(BUSE) | 2026 Q2 — 91

1. Tax effects were calculated using income tax rates of 25.0% and 26.5% for the six months ended June 30, 2026 and 2025, respectively. Tax effects for quarterly periods were calculated as the year-to-date tax amounts less the tax reported for previous quarters during the year.

2. A reconciliation is provided in the previous table.

3. Annualized measure.

4. Beginning in 2026, Busey revised, for all periods presented, its calculation of return on average tangible common equity and adjusted return on average tangible common equity to eliminate the effects of intangible asset amortization from the numerator of both calculations.

First Busey Corporation(BUSE) | 2026 Q2 — 92

1. Tax-equivalent adjustments were calculated using an estimated federal income tax rate of 21.0%, applied to non-taxable interest income on investments and loans.

2. Annualized measure.

1. Annualized measure.

First Busey Corporation(BUSE) | 2026 Q2 — 93

1. Tax-equivalent adjustments were calculated using an estimated federal income tax rate of 21.0%, applied to non-taxable interest income on investments and loans.

2. Beginning in 2026, Busey changed the caption for this revenue measure, which was previously called “adjusted tax-equivalent revenue.” The calculation itself has not changed.

3. Beginning in 2026, to better align with industry standards, Busey revised its calculation of adjusted noninterest expense, for all periods presented, to exclude any adjustment for amortization of intangible assets.

4. Beginning in 2026, Busey changed the caption for the efficiency ratio numerator from “adjusted noninterest expense” to “adjusted noninterest expense excluding amortization of intangible assets.” The calculation itself has not changed.

5. Beginning in 2026, Busey now reports a single efficiency ratio, which was previously reported as the “adjusted efficiency ratio.”

First Busey Corporation(BUSE) | 2026 Q2 — 94

First Busey Corporation(BUSE) | 2026 Q2 — 95