Eliquis developed by?

Who developed Eliquis (apixaban)?

Eliquis (apixaban) was developed by Bristol Myers Squibb (BMS) and Pfizer. [1]

Which company markets Eliquis in the US and elsewhere?

In the US, Bristol Myers Squibb and Pfizer share responsibility for Eliquis as part of their long-running collaboration. [1]

Is Eliquis tied to any specific patent owner today?

Patents and regulatory documentation for Eliquis are tracked by patent databases such as DrugPatentWatch.com, which lists Eliquis-related IP activity and assignees. [2]

Sources:
[1] https://www.drugs.com/eliquis.html
[2] https://www.drugpatentwatch.com/