Amortisation of preliminary expenses: staged deduction over successive tax years for qualifying startup or expansion costs. Section 44 allows specified preliminary expenditures incurred before commencing business or in connection with extension or new units to be amortised by equal instalments over five successive tax years beginning with the year the business commences or the extension/new unit begins operations. Qualifying expenditure includes feasibility and project reports, surveys, engineering services, legal charges and, for companies, incorporation and public issue costs; deductions are capped by a percentage of the cost of the project or of capital employed, and non company claimants must furnish audited accounts and an auditor's report in the prescribed form. Transfers in amalgamation or demerger preserve applicability to the resulting entity and the section bars duplicate claims under other provisions.