X0306 4 2020-05-20 0000929940 ASPEN TECHNOLOGY INC /DE/ AZPN 0001560263 Johnsen Karl E C/O ASPEN TECHNOLOGY, INC. 20 CROSBY DRIVE BEDFORD MA 01730 1 Senior Vice President and CFO Common Stock 2020-05-20 4 M 0 11456 45.46 A 33770 D Common Stock 2020-05-20 4 M 0 12616 63.25 A 46386 D Common Stock 2020-05-20 4 M 0 4374 37.91 A 50760 D Common Stock 2020-05-20 4 S 0 29692 95.07 D 21068 D Employee Stock Option (Right to Buy) 45.46 2020-05-20 4 M 0 11456 0 D 2026-08-31 Common Stock 11456 2866 D Employee Stock Option (Right to Buy) 63.25 2020-05-20 4 M 0 12616 0 D 2027-08-31 Common Stock 12616 5735 D Employee Stock Option (Right to Buy) 37.91 2020-05-20 4 M 0 4374 0 D 2025-09-30 Common Stock 4374 7265 D The option granted at the exercise price of $45.46 vests in 16 equal consecutive quarterly installments on the last business day of the quarter, beginning on September 30, 2016. The option granted at the exercise price of $63.25 vests in 16 consecutive equal quarterly installments on the last business day of the quarter, beginning on September 29, 2017. The option granted at the exercise price of $37.91 vests in 16 equal consecutive quarterly installments on the last business day of the quarter, beginning on December 31, 2015. The price reported in Column 4 is a weighted average price. These shares were sold in several transactions at prices ranging from $94.81 to $95.50, inclusive. The reporting person undertakes to provide to Aspen Technology, Inc., any security holder of Aspen Technology, Inc., 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 range set forth in this footnote. /s/ F. G. Hammond, attorney-in-fact for Mr. Johnsen 2020-05-21