X0306 4 2018-07-05 0 0000002034 ACETO CORP ACET 0001220091 EILENDER ALBERT L 4 TRI HARBOR COURT PORT WASHINGTON NY 11050 1 1 0 0 Chairman COMMON STOCK 2018-07-05 4 S 0 3800 3.6809 D 305372 D Automatic sale under Rule 10b5-1 to cover the Reporting Person's tax obligation in connection with the vesting of an equity award(s) granted previously. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.66 to $3.69. The reporting person undertakes to provide to Aceto, any security holder, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth above. /s/ Albert Eilender 2018-07-05