If I take the example of GDSI, MT gives a low at 0,0055 but a open at 0,0045. The open is wrong and this result in a to low candle on the historical chart. However the next day the candel from the day before becomes right with a low at 0,0055. This appens every day with a lot of stocks. I suppose the reason lies with Yahoo? ( I have delayed quotes from Yahoo ).