Why did Coal India stock get decreased by 5% after the announce of of dividend?

Dividend is announced on the face value of the stock, once it is announced every stock will be down by the same as dividend paid, it mean that some part of the growth in your investment is returned to you in the way of dividend, So it will be reduced by the same amount.

Even in coal india case is also the same, it has announced a of RS 20.70/- of interim dividend, a 207% on face value.

Read this statement from NSE web site:-

Coal India Limited has informed the Exchange that the Board of Directors of the Company at its meeting held on February 27, 2015 have approved payment of Interim Dividend for the financial year 2014-15 @ Rs. 20.70/- (Twenty rupees and seventy paise only) per share of the face value of Rs.10/- as recommended by the Audit Committee of the Company in its meeting held on February 27, 2015.

Coal India Limited has informed the Exchange that the date of payment of interim dividend is on and from March 10, 2015.

Thanks Praveen.