Accounting Ops Associate: AP/AR, Treasury & Systems

Mainstay; United States; On-site; USD 55,000 - 85,000; Full time

Job summary

Mainstay, the leading market intelligence platform for the single-family rental industry, is seeking an Accounting Operations Associate in the United States. You will own AP/AR cycles, support treasury, and be the primary owner of financial systems.

This role offers growth into broader accounting, cash management, and finance operations within a fast-growing startup environment. As part of the finance team, you will manage vendor relationships, oversee daily cash positions, and help ensure data

Qualifications

• 1–3 years in accounting/finance with hands-on AP/AR experience.
• Exposure to treasury/cash management tasks is a strong plus.
• Experience administering financial systems (ERP, AP/AR, or banking portals).
• Strong Excel and ability to work across multiple financial systems.
• Detail-oriented with deadline-driven controls and accuracy.

Responsibilities

• Own full AP cycle: invoices, coding, approvals, payments, vendor terms.
• Own full AR cycle: invoicing, collections, cash receipts, aging.
• Manage treasury/cash management tasks and bank reconciliations.
• Administer financial systems, integrations, and SOP documentation.
• Support month-end close, reporting, and basic FP&A tasks.
• Assist with payroll and employee expense processing.

Skills

AP/AR

Treasury

ERP

Excel

Attention to detail

Communication

Education

Accounting/Finance degree (preferred)

Tools

ERP systems

AP/AR platforms

Banking portals

Job description

Mainstay, the leading market intelligence platform for the single-family rental industry, is seeking an Accounting Operations Associate in the United States. You will own AP/AR cycles, support treasury, and be the primary owner of financial systems.

This role offers growth into broader accounting, cash management, and finance operations within a fast-growing startup environment. As part of the finance team, you will manage vendor relationships, oversee daily cash positions, and help ensure data