Whenever abbreviations whose meaning is not immediately obvious are used in the content, the full form of the abbreviation must be shown the first time the abbreviation is used on the page.
So, for the first occurrence, rather than writing “The increase in EBITDA in the last three years…” write “The increase in earnings before interest, taxes, depreciation and amortization (EBITDA) in the last three years…”.
Further down the page you can use the abbreviation “EBITDA” on its own when you want to write about earnings.