Dividends can either be accounted for in current positions or closed positions. How are they determined?
Each share gains dividends and once that share is sold (i.e. closed position), the dividends gained are shifted to closed positions.
Buy 100 of share of company A at 1st Feb 2018 @ SGD 1 per share (Cost: SGD100)
Dividends with ExDate on 1st March 2018 @ SGD 0.05 for company A (Yield = 5% and Total Amount = SGD 5)
Sell 50 shares of company A
=> At this point, SGD2.5 of the dividends will be accounted for in current positions and SGD2.5 of the dividends will be accounted for in closed positions.