Stacking refers to the total financial assistance that can be received from different government sources for a given project. There are upper limits on total government assistance depending on whether the funding is for a social program, economic program, or R&D. Government assistance agreements must state the percentage of total government assistance to avoid exceeding stacking limits. While many R&D programs provide funding before work begins, SR&ED tax incentives are obtained after work is completed through tax filings, creating uncertainty around stacking calculations. Pre-claim reviews are available to help determine SR&ED eligibility and avoid potential issues with exceeding stacking limits.