Executive Assistant & Office Manager

Ostium is on a simple mission: make it possible for anyone with a digital wallet to trade stocks, commodities, currencies, and crypto with full transparency. No brokers, no freezes, no hidden spreads. We’re replacing the opaque, offshore brokerage model with a transparent, permissionless trading stack built onchain. Every trade, deposit, and withdrawal is verifiable through open, auditable code. We’ve raised $27.9M+ from General Catalyst, Jump, LocalGlobe, Susquehanna (SIG), GSR, Alliance DAO, Soma Capital, Balaji Srinivasan, Meltem Demirors, and others.

Role (New York / Full-time)

We are looking for an experienced and highly resourceful Executive Assistant & Office Manager to support the executive team. This is a high-trust, high-visibility role at the center of the company — you will be the person the executive team relies on to protect their time, maintain their focus, and ensure the office runs flawlessly.

The right candidate has supported C-suite executives or senior management in a fast-paced, high-standards environment and brings the judgment, discretion, and proactive instincts to operate with minimal oversight. In addition to supporting the executives directly, this person will work closely with Ostium's Operations team.

What you'll do

Executive Support

• Own and manage the executive team's complex calendars, inboxes, and correspondence — prioritizing ruthlessly and closing loops without being asked

• Act as gatekeeper, protecting executives' time and filtering requests with sound judgment

• Prepare for and coordinate meetings across investors, partners, and internal teams including agendas, pre-reads, and follow-ups

• Arrange complex domestic and international travel with seamless logistics

• Prepare and submit expense reports accurately and on time

• Handle all sensitive and confidential information with absolute discretion and good judgment

Office Management

• Serve as the face of Ostium's NYC office — welcoming guests and setting the tone for our culture

• Own all office operations: facilities, vendors, supplies, equipment, and day-to-day logistics

• Manage incoming mail and deliveries

• Support employee onboarding, team events, and off-sites

• Manage office budgets, invoices, and service contracts

• Partner with the operations team to ensure seamless day-to-day support across the office

• Take on ad hoc projects and operational needs as they arise

Who you are

• 5-10 years of experience supporting C-suite executives and senior management; background in investment banking, a hedge fund, or a high-growth startup preferred

• Proven track record managing complex calendars and travel logistics for senior executives

• Exceptionally organized, detail-oriented, and proactive — you solve problems before they surface

• Polished communicator across all mediums; high EQ and strong relationship-building skills

• Calm under pressure, discreet, and trustworthy with sensitive information

• Genuinely excited to be in the NYC office five days a week

• Proficient in Google Workspace, Slack, Notion, and standard expense management tools; quick to adopt new systems

• Bachelor's degree preferred

What we offer

• Competitive compensation package

• Equity in a well-capitalized, high-growth company

• Collaborative environment with a highly skilled team

• Professional development opportunities