imo could it be related to GSK's agreement to acquire IDRX, inc? It looks like it was announced last month. Granted its not HIV related, but they are committing $1 billion upfront according to the article, but would fulfill what was said on here that normally the acquirer's stock price goes down initally?:


https://www.gsk.com/en-gb/media/press-release...-idrx-inc/