Social Media Lead - Thirdbase Capital

About Thirdbase Capital

Thirdbase Capital is a growth-stage venture platform investing in AI, defense, frontier tech, robotics, energy, and fintech. Our portfolio includes some of the most sought-after private companies in AI and deep tech. We are now building the internal technology that will define how we source and underwrite the next decade of investments.

The Role

• This role owns the public voice of Thirdbase. It has three parts:
• Grow our Twitter/X and social presence. Build the firm's following with sharp, consistent content that founders, LPs, and operators want to read.
• Build the personal brand of our General Partner. Ghostwrite threads, posts, and essays in his voice. Position him as a leading voice in AI, defense, and frontier tech investing. Help him land podcasts, panels, and press.
• Grow our newsletter. Take our newsletter and scale it into a must-read for the venture and LP community. Own the content, the growth plan, and the numbers.

Responsibilities

• Build and run the content plan across Twitter/X, LinkedIn, and the newsletter
• Ghostwrite for the GP and develop his personal brand week by week
• Turn our investment ideas (AI infrastructure, defense tech, frontier hardware, fintech) into threads, essays, and market commentary
• Grow followers and newsletter subscribers with a clear, measurable plan
• Track what works: engagement, subscriber growth, and inbound deals and LP interest that come from content
• Try new formats: deal breakdowns, market maps, founder spotlights, LP-facing insights

What We Are Looking For

• A proven track record. A Twitter/X account, newsletter, or personal brand grown with real numbers behind it (followers, subscribers, open rates, engagement)
• Newsletter experience. Someone who has built a newsletter from scratch or scaled one from small to large (Substack, Beehiiv, or similar) and understands growth, referrals, and retention
• VC knowledge. Time spent in or around venture capital, at a fund, in a platform or content role, or close to the ecosystem as a founder or operator. A clear grasp of fund structures and what LPs and founders care about
• Ghostwriting skill. The ability to write in someone else's voice
• Strong writing. Clear, fast, and flexible across formats.

Nice to Have

• An existing audience or network in tech or VC circles on Twitter/X
• Experience building a public profile for a founder, investor, or executive
• Knowledge of AI, defense, or frontier tech markets
• Experience supporting fundraising or LP communications
• Basic design skills (charts, market maps, deck-quality graphics)

How to Apply

Send the following to [email protected]

• Links to accounts, newsletters, or personal brands you have grown, with before and after numbers
• CV
• 2 to 3 writing samples (threads, essays, or newsletter issues)