851.22.23.6. If, at the end of a particular taxation year of a taxpayer who is a financial institution for the year, the taxpayer holds a share of the capital stock of a corporation, the taxpayer has a significant interest in that corporation at any time in the year and the share is a mark-to-market property of the taxpayer for the subsequent taxation year, the taxpayer is deemed to have disposed of the share immediately before the end of the particular year for proceeds of disposition equal to the fair market value, at that time, of the share, and to have acquired the share at the end of the particular year at a cost equal to those proceeds.