Can my estate get a refund if I overpaid Estate Administration Tax based on an early estimate?

Yes — Ontario's Estate Administration Tax is initially paid based on the estate trustee's own estimate of the estate's value at the time the certificate of appointment is applied for, and that estimate can turn out to be too high once the actual value of the assets is confirmed. If the tax paid turns out to exceed what was actually owed based on the true value, the estate trustee can apply for a reassessment and refund of the overpayment.

This most often comes up where an asset was valued conservatively-high at the outset, before a proper appraisal, before a sale price was known, or before a debt or liability affecting the estate's net value came to light, and the corrected figure is lower once the Estate Information Return is filed with accurate values. Because the Estate Information Return has to be filed within a set window after the certificate is issued and can itself trigger scrutiny or an assessment either way, an estate trustee who believes the original estimate was too high should raise it with an advisor promptly rather than waiting, so the correction and any refund claim are made properly and on time.