Business Plus is Upwork's paid plan for clients, between the free Marketplace plan and Upwork Enterprise, which for a subscription and different fee terms adds team features, shared billing and Upwork's talent sourcing and support.
Upwork sells to clients in tiers. The basic Marketplace plan is free to join and charges the client marketplace fee and the contract initiation fee as contracts are paid. Business Plus is the first paid step: a monthly subscription, priced by Upwork, in exchange for which the client pays fees on different terms, can add several team members under one account with shared billing and reporting, and gets a dedicated level of support, sourcing help from Upwork's recruiters and access to curated or pre-screened talent. Above it, Upwork Enterprise is a negotiated contract for large companies with compliance and payroll services, reported by Upwork Inc. as managed services rather than marketplace revenue.
What is included, and the fee rates that apply on the plan, are set by Upwork, stated in the Help Center and changed from time to time, so the plan is best understood as "a client who pays for more from Upwork" rather than by any fixed feature list.
For freelancers and agencies the plan is invisible on a job post but not irrelevant. Business Plus clients tend to be companies rather than individuals, to hire for longer, and to be routed to talent through Upwork's own sourcing, including Talent Scout, which favours profiles with badges and a strong Job Success Score. The subscription itself is paid by the client and does not affect the freelancer's fee.
How Upwork Insights uses it
This term describes Upwork's own rules or product rather than a figure the index measures; the pages that do carry live figures are the stats and rate pages.