Reserve account transfer to surplus.

If any transfer of a reserve or other account or portion thereof is in effect a transfer to surplus, so much of such transfer as had been accumulated through deductions from the gross or taxable income of the years open to audit under s. 71.74 (1) and (2) shall be included in the gross or taxable income of such years, and so much of such transfer as has been accumulated through deductions from the gross or taxable income of the years following January 1, 1911, and not open to audit under s. 71.74 (1) and (2) shall be included in the gross or taxable income of the year in which such transfer was effected.