Reopening limitation for wealth-tax assessments: extended window where significant escaped net wealth permits later reassessment. The amendment substitutes clauses (a) and (b) of sub section (1A) of section 17 to provide that reassessment is generally permitted after four years from the end of the relevant assessment year, and that where four but not more than six years have elapsed reassessment is permitted only if the net wealth chargeable to tax which has escaped assessment amounts to or is likely to amount to the prescribed threshold.