The stock tumbled 67.45 per cent to Rs 142.50 -- its 52-week low at the BSE.
On the NSE, it crashed 67.46 per cent to hit its one-year low of Rs 142.50.
Mastek on June 4 informed BSE that June 15 has been fixed as record date for the purpose of determining the members of Mastek Ltd to which shares of Minefields Computers will be allotted in the ratio of 1:1.
The scheme of arrangement involves demerger of insurance products and service business of Mastek into Minefields Computers, followed by slump sale of Offshore Insurance Operations by Minefields Computers Pvt Ltd (MCPL) to Majesco.
The stock turned ex-date today to reflect the spin-off.
Meanwhile, the benchmark BSE Sensex was trading at 26,480.28, up 109.30 points.