| SC 13G | 2016-02-16 | ALLIANCEBERNSTEIN L.P. | ASPEN TECHNOLOGY INC /DE/ | 4,444,289 | 5.3% | EDGAR |
| SC 13G/A | 2016-02-12 | WADDELL & REED FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 5,306,412 | 6.4% | EDGAR |
| SC 13G/A | 2016-02-10 | VANGUARD GROUP INC | ASPEN TECHNOLOGY INC /DE/ | 7,585,718 | 9.1% | EDGAR |
| SC 13G | 2016-02-02 | Artisan Partners Limited Partnership | ASPEN TECHNOLOGY INC /DE/ | 5,674,805 | 6.8% | EDGAR |
| SC 13G/A | 2016-01-25 | BlackRock Inc. | ASPEN TECHNOLOGY INC /DE/ | 5,223,192 | 6.3% | EDGAR |
| SC 13G/A | 2015-02-13 | WADDELL & REED FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 10,333,490 | 6.0% | EDGAR |
| SC 13G/A | 2015-02-10 | VANGUARD GROUP INC | ASPEN TECHNOLOGY INC /DE/ | 7,298,979 | 8.1% | EDGAR |
| SC 13G/A | 2015-01-22 | BlackRock Inc. | ASPEN TECHNOLOGY INC /DE/ | 7,696,478 | 8.5% | EDGAR |
| SC 13G/A | 2014-02-14 | FMR LLC | ASPEN TECHNOLOGY INC /DE/ | 3,954,024 | 4.3% | EDGAR |
| SC 13G/A | 2014-02-11 | VANGUARD GROUP INC | ASPEN TECHNOLOGY INC /DE/ | 5,962,848 | 6.4% | EDGAR |
| SC 13G/A | 2014-02-07 | WADDELL & REED FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 9,426,425 | 10.1% | EDGAR |
| SC 13G/A | 2014-01-28 | BlackRock Inc. | ASPEN TECHNOLOGY INC /DE/ | 7,099,751 | 7.6% | EDGAR |
| SC 13G/A | 2013-02-14 | FMR LLC | ASPEN TECHNOLOGY INC /DE/ | 6,008,128 | 6.4% | EDGAR |
| SC 13G | 2013-02-13 | VANGUARD GROUP INC | ASPEN TECHNOLOGY INC /DE/ | 5,335,920 | 5.7% | EDGAR |
| SC 13G/A | 2013-02-07 | WADDELL & REED FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 11,972,289 | 12.8% | EDGAR |
| SC 13G | 2013-01-30 | BlackRock Inc. | ASPEN TECHNOLOGY INC /DE/ | 5,903,402 | 6.3% | EDGAR |
| SC 13G/A | 2012-02-14 | CADIAN CAPITAL MANAGEMENT, LLC | ASPEN TECHNOLOGY INC /DE/ | 87,983 | 0.1% | EDGAR |
| SC 13G/A | 2012-02-14 | AMERIPRISE FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 1,184,068 | 1.3% | EDGAR |
| SC 13G/A | 2012-02-14 | WADDELL & REED FINANCIAL INC | ASPEN TECHNOLOGY INC /DE/ | 5,393,247 | 5.8% | EDGAR |
| SC 13G | 2012-02-14 | FMR LLC | ASPEN TECHNOLOGY INC /DE/ | 6,993,538 | 7.4% | EDGAR |