AI in Call Centers: Autonomous Voice AI Agents (Sierra, Bland AI, Vapi) and Intelligent Agent Assist (Cresta, Gong)

Of the $300 billion (approximately ¥45 trillion) in global venture investment during Q1 2026, AI-related deals accounted for roughly $242 billion (approximately ¥36.3 trillion), or 80%, with the voice AI agent and agent-assist domains becoming the most heated segments within. Sierra, led by Bret Taylor, reached a $10 billion (approximately ¥1.5 trillion) valuation with $150 million (approximately ¥22.5 billion) in ARR, while developer platform Vapi, enterprise telephony automation provider Bland AI, and contact center-focused Cresta and [Gong](https://newsify.tv/services/gong) are absorbing massive Silicon Valley VC capital across the two axes of autonomous agents and agent assist. This article provides an integrated analysis of each company's latest status, the investment theses drawn by [Sequoia](https://newsify.tv/investors/sequoia-capital), [a16z](https://newsify.tv/investors/andreessen-horowitz), [Bessemer](https://newsify.tv/investors/bessemer-venture-partners), and [Greylock](https://newsify.tv/investors/greylock-partners), the editorial stance of various media outlets, and milestones from the second half of 2026 onward. ---