Shares of Stop-n-Go Stores parent Casey's General Stores Inc. sank 5% toward a three-year low in morning trade Tuesday, after the operator of convenience stores and gas stations reported fiscal fourth-quarter profit and revenue that missed expectations, citing "suppressed fuel margin and challenging weather." Net income for the quarter to April 30 fell to $19.3 million, or 51 cents a share, from $30.1 million, or 76 cents a share, in the same period a year ago. The FactSet consensus for earnings per share was 66 cents. Revenue rose to $2.09 billion from $1.85 billion, but missed the FactSet consensus of $2.12 billion. Same-store gallons rose 2.0%, missing the FactSet consensus for 3.0% growth, as average margin of 16.3 cents per gallon was well below the full-year average margin of 18.5 cents per gallon. Same-store sales for grocery and other merchandise fell 0.4%, while the FactSet consensus was for a rise of 2.6%, and the 1.3% decline in prepared food and fountain same-store sales missed expectations of a 2.2% rise. The stock, which was trading at the lowest level since June 2015, has now tumbled 18% year to date, while the SPDR S&P Retail ETF has rallied 11% and the S&P 500 has gained 4.3%.