Datadog will replace Juniper Networks in the benchmark index after HPE completed its $13.4 billion acquisition of the networking equipment maker1. The New York-based company, which provides monitoring software for cloud applications, saw its shares rise to $153.33, up 13.6% from Wednesday's close2.

The inclusion represents a milestone for Datadog, which went public in 2019 and reported revenue of $762 million in the first quarter of 20253. The company has struggled this year, declining 5.5% year-to-date compared to the Nasdaq's 5.6% gain4. Index funds and institutional portfolios that track the S&P 500 will now be required to purchase Datadog shares, typically boosting trading volumes and providing price support.

Synopsys shares extended their recent gains, rising 2% Wednesday for a sixth consecutive day of increases1. The semiconductor design software maker has seen its stock climb 8.96% over six trading sessions as its $35 billion merger with engineering software company Ansys moves toward completion1.

Both companies said in a joint statement Monday they have received merger clearance in every jurisdiction except China and are "at an advanced stage in obtaining this final regulatory approval"2. Chinese regulators had initially postponed approval amid trade tensions, but recent reports suggest the deal remains on track3.

Tripadvisor shares jumped 17.3% to $17.50 after activist investor Starboard Value disclosed a 9% stake worth approximately $160 million1. According to Trading View, Starboard called the online travel company's shares "undervalued" and said they represent an "attractive investment opportunity"1.

The investment comes after Tripadvisor formed a special committee last year to explore a potential sale but ultimately determined such a move was against the company's interests1. Starboard plans to engage with management on value creation opportunities.