** Shares of Ampol ALD.AX fall as much as 2.1% to A$20.860, their lowest since April 9
** Australia's top fuel retailer posts a 49% drop in its first-quarter refining margins for its Lytton refinery in Australia's Queensland, hurt by weakness in refining profits in Singapore
** Ouput in the Lytton refinery for the quarter dropped 5.7% to 1.30 billion litres
** Shares of co last down 1.2%
** YTD, shares down 25.4%
(Reporting by Nichiket Sunil in Bengaluru)
((Nichiket.Sunil@thomsonreuters.com))