InterDigital, Inc.

APPENDIX A

Adjusted EBITDA and Adjusted EBITDA margin are supplemental non-GAAP financial measures that InterDigital believes provide investors with important insight into the Company's ongoing business performance. InterDigital defines Adjusted EBITDA as net income attributable to InterDigital Inc. plus net loss attributable to non-controlling interest, income tax (provision) benefit, other income (expense) & interest expense, depreciation and amortization, share-based compensation, and other items. Other items include restructuring costs, impairment charges and other non-recurring items. Adjusted EBITDA margin is Adjusted EBITDA over total revenue. These non-GAAP financial measures used by the company may be calculated differently from, and therefore may not be comparable to, similarly titled measures used by other companies. The presentation of these financial measures, which are not prepared under any comprehensive set of accounting rules or principles, is not intended to be considered in isolation or as a substitute for the financial information prepared and presented in accordance with GAAP. A reconciliation of Adjusted EBITDA to the most directly comparable GAAP financial measure is provided below.

(a) Other items in the above table includes litigation fee reimbursements, impairments, restructuring costs, transactional costs and other non-recurring items.

Pro Forma EBITDA is a supplemental non-GAAP financial measure that InterDigital uses for compensation purposes as described in this proxy statement. InterDigital defines Pro Forma EBITDA as total revenues minus operating expenses plus depreciation and amortization, intellectual property enforcement costs, share-based compensation, and other items. Other items include restructuring costs, impairment charges and other non-recurring items, as further described below. This non-GAAP financial measure may be calculated differently from, and therefore may not be comparable to, similarly titled measures used by other companies. A detailed reconciliation of Pro Forma EBITDA to the most directly comparable GAAP financial measure is provided below.

Non-GAAP net income, Non-GAAP EPS, and Non-GAAP weighted-average diluted shares are supplemental non-GAAP financial measures that InterDigital believes provides investors with important insight into the Company's ongoing business performance. InterDigital defines Non-GAAP net income as net income attributable to InterDigital, Inc. plus share-based compensation, acquisition related amortization, depreciation and amortization, restructuring costs, impairment charges and one-time adjustments, losses on extinguishments of long-term debt, the related income tax effect of the preceding items, and adjustments to income taxes. Non-GAAP EPS is defined as Non-GAAP net income divided by Non-GAAP weighted average diluted shares, which adjusts the weighted-average number of common shares outstanding for the dilutive effect of the Company's convertible notes, offset by our hedging arrangements. InterDigital’s computation of these non-GAAP financial measures might not be comparable to similarly named measures reported by other companies. The presentation of these financial measures, which are not prepared under any comprehensive set of accounting rules or principles, is not intended to be considered in isolation or as a substitute for the financial information prepared and presented in accordance with GAAP. A reconciliation of each of these metrics to its most directly comparable GAAP financial measure is provided below.

(a) Other operating items in the above table includes litigation fee reimbursements, impairments, restructuring costs, transactional costs and other non-recurring items.

(b) Other non-operating items in the above table includes net gains from observable price changes of our long-term strategic investments, losses on the extinguishment of debt, pension and debt revaluations, and other non-recurring non-operating items.