SRED is a tax credit so it should be treated as other income, not part of EBITDA. EBITDA should be representative of the commercial operating aspects of the business for the purposes of valuation. Same logic on things like government grants - it's not a commercial source of income and should be excluded from the valuation of the business. Another thing to keep in mind is that SRED subsidizes your R&D labour but you still need to fund the working capital until you receive your refund, unless you start getting into financing accrued SRED (which is expensive).

A range of treatments of SR&ED are already covered here. One approach I have not seen mentioned is valuing the operating business cash flows and the SR&ED-related cashflows separately, given their different risk profiles. The operating business would be valued based on its core cash-generating ability, with the benefits of SR&ED naturally reflected in margins, growth, and potentially the trading multiple. The SR&ED cash flows, similar to other recurring subsidized cash flow streams expected to persist, will be modeled separately as a risk-adjusted annuity. Where the cash flow is probability-weighted and the discount rate is built-up reflecting the associated policy, audit, documentation, and continuity risks