- A joint SR&ED filing is when schedule T661, which describes the SR&ED projects, is included as part of the original corporate T2 tax filing. This must be done within 6 months of the corporate financial year end, the filing deadline for the T2.
- An amended filing is when the T661 is filed separately, after the T2 has already been filed. The filing deadline is 18 months from the corporate financial year end.
- A joint filing is much preferred because you get paid much more quickly, and industry experience shows that the chance of an audit is reduced.
