Leidos — Feb 11, 2025 release

Exhibit 99.1 2 FORWARD GUIDANCE Leidos is initiating fiscal year 2025 guidance as specified in the table below. Measure FY25 Guidance Revenues (billions) $16.9 - $17.3 Adjusted EBITDA Margin Mid-High 12% Non-GAAP Diluted EPS $10.35 - $10.75 Cash Flows Provided by Operating Activities (billions) Approximately $1.45 For information regarding adjusted EBITDA margin and non-GAAP diluted EPS, see the related explanations and reconciliations to GAAP measures included elsewhere in this release. Leidos does not provide a reconciliation of forward-looking adjusted EBITDA margins or non-GAAP diluted EPS to net income margin or diluted EPS, due to the inherent difficulty in forecasting and quantifying certain amounts that are necessary for such reconciliation. Because certain deductions for non-GAAP exclusions used to calculate projected net income may vary significantly based on actual events, Leidos is not able to forecast on a GAAP basis with reasonable certainty all deductions needed in order to provide a GAAP calculation of projected net income margin, diluted EPS or net income attributable to Leidos shareholders at this time. The amounts of these deductions may be material and, therefore, could result in projected net income margin, net income attributable to Leidos shareholders and diluted EPS being materially less than projected adjusted EBITDA margins and non-GAAP diluted EPS. 3 Leidos Holdings, Inc. Exhibit 99.1 CONFE