Capital Floods the Support-Agent Layer: Sierra Raises $950M Series E (~$1.585B Total) as Decagon Sits at $4.5B

Sacra·low signal

Sierra closed a $950M Series E led by GV and Tiger Global, pushing total funding to ~$1.585B, while Decagon's January round set its valuation at $4.5B — the two leaders in AI-native customer support are now capitalized like infrastructure plays. The money chases a real wedge: outcome-priced agents that resolve tickets end-to-end rather than deflect them, eating into Zendesk/Intercom seat revenue. For builders, the support category has effectively closed to new entrants without nine-figure backing.