Old Mission Internship 2027–2028: Programs, Pay & How to Apply

Last updated: July 2026

Old Mission's 2027 SWE internship posts a salary range of $150,000 to $200,000 annualized with free corporate housing, placing it among the highest-paying internships in quantitative finance. The firm is a global quantitative market maker trading trillions of dollars across equities, bonds, currencies, and derivatives with roughly 200 employees across Chicago, New York, and London. Cohort sizes are small: the NUFT internship tracker notes Old Mission takes approximately 4 interns for its winter program, and the summer SWE cohort is comparably selective. The 2027 application window opened in mid-July 2026 and is expected to close by mid-August, giving you roughly four to five weeks from open to close.

Quick Facts

Two numbers frame the opportunity: $150,000 to $200,000 annualized intern pay and a 4- to 5-week application window that closes by mid-August. Old Mission runs small cohorts at a firm with 200+ employees, and the HackerRank OA is described by candidates as one of the hardest in the industry. Apply early and prepare aggressively.

Externships are short, remote projects where you finish real work for a real company. The Wayfair AI Agent Engineering Externship and Beats by Dre Data Analytics Externship build the programming, quantitative analysis, and systems-thinking evidence an Old Mission application and its notoriously difficult HackerRank OA reward. Explore all Externships.

What Is an Old Mission Internship?

An Old Mission internship is a paid, full-time placement at a global quantitative market maker that trades trillions of dollars across asset classes using proprietary systems. Unlike large banks or asset managers, Old Mission is a 200-person firm where interns work directly alongside senior traders and engineers on real production systems from day one. The SWE internship runs 10 to 12 weeks in Chicago, focused on building C++ trading applications and tools that impact daily firm operations. Interns receive educational sessions with senior engineers and collaborate across trading, research, and technology teams. The firm provides free corporate housing and daily meals. On Glassdoor, Old Mission holds a 4.2 out of 5 rating with 97% of employees recommending the company to a friend and a 4.6 out of 5 for career opportunities. The flat hierarchy means founders remain on the trading floor, and interns interact with them directly.

When Do Old Mission Internship Applications Open for 2027–2028?

Old Mission's recruiting calendar is fast and narrow. For the Summer 2027 SWE internship, university portal postings appeared July 13 to 15, 2026, with expiry dates of August 13 to 15, giving a window of roughly four to five weeks. The process from application to offer runs 1 to 2 months per Wall Street Oasis. The winter Quant Trader micro-internship (January 2027) recruits on a similar compressed schedule in the preceding fall. The critical insight: Old Mission runs small cohorts, likely reviews applications on a rolling basis, and Reddit reports candidates being rejected before even completing their OA, suggesting aggressive early screening. Apply the day the posting goes live.

Why You Must Apply the Week Applications Open

The application window is the bottleneck, not the interview. Old Mission's 2027 SWE internship window is roughly four to five weeks, from mid-July to mid-August 2026. Reddit reports candidates being rejected before completing their OA, suggesting the firm runs aggressive resume screening in parallel with OA distribution and fills seats as strong candidates emerge. With cohort sizes as small as 4 for the winter micro-internship and comparably selective summer numbers, every day you wait is a day closer to a closed posting. Apply the day you see the listing on oldmissioncapital.com/careers. And prepare for the OA before you apply: the HackerRank assessment is described by candidates as one of the hardest in the industry, with 30 MCQs in 60 minutes covering DSA, C++, Python, OOP, and systems concepts.

Which Old Mission Internship Programs Should You Target?

Old Mission runs a lean set of university programs, each with small cohorts and direct exposure to production systems. Unlike large banks with rotational intern classes of 50 or more, Old Mission places interns directly onto trading or engineering teams. Which track should you target? SWE if your strength is systems programming in C++, quant trading if your strength is probability and mathematical modeling.

See every open role on the Old Mission careers page. Note the firm's emphasis on C++ for trading applications: this is not a Java or Python shop. If your strongest language is C++ and you want to apply it to low-latency systems, Old Mission is a direct fit.

What Are the Eligibility Requirements?

Old Mission's requirements are role-specific, but the core lines are consistent:

• Enrollment: currently pursuing a Bachelor's or Master's degree in Computer Science, Computer Engineering, or a related quantitative field (Engineering, Mathematics, Statistics, Physics).

• Graduation window: December 2027 or May 2028 for the summer 2027 SWE internship. Junior standing or higher required.

• GPA: minimum 3.0 on a 4.0 scale for SWE roles (explicitly stated in the job posting).

• Work authorization: Old Mission sponsors H-1B visas (median H-1B salary of $162,500 per Ellis data), suggesting openness to international students, a notable difference from many finance firms.

• Finance experience: explicitly not required for the SWE internship. A genuine interest in financial markets and understanding software's role in trading is valued but not mandatory.

• Ethics emphasis: all listings mention proven trustworthiness and performance under the highest ethical standards.

Does Old Mission Have a Hard GPA Cutoff?

The SWE internship posting lists a minimum 3.0 GPA, and this appears to be a hard filter given the competitive nature of the firm. But beyond the GPA floor, Old Mission's OA is the real gatekeeper. Candidates consistently describe the HackerRank assessment as one of the hardest in the industry, with deep CS fundamentals, C++ specifics, and medium-to-hard coding problems. A 4.0 GPA will not save you if you cannot clear the OA, and a 3.0 GPA will not stop you if your systems programming skills are sharp.

What Skills Does Old Mission Look For, and How Do You Build Them?

Read across four Old Mission job listings, one SWE intern, one Quant Trader micro-intern, one SWE graduate program, and one Quant Trader graduate program, and the pattern is clear. Python appears in all four. C++ appears in three, reflecting its dominance as the firm's primary language for trading applications. Probability and statistics appear in three. Communication and collaboration appear in all four. But the skill list only tells half the story. Old Mission's OA tests deep CS fundamentals including data structures, algorithms, OOP, and systems concepts at a difficulty level candidates call the hardest they have encountered. So bring the language fluency, then wrap every answer in systems-level thinking.

How Is Demand for Quantitative Finance Interns Moving Right Now?

Build These Skills Before You Apply

And every skill in that chart maps to a remote Externship where you finish a real project before a role opens.

How close is the overlap? The Wayfair project is agent-engineering work that yields the build-and-explain evidence Old Mission's systems-focused interviews probe for, and the Beats project ends on the quantitative-analysis story that demonstrates the data-driven thinking quant firms value.

What Is the Old Mission Application and Interview Process Like?

Old Mission's funnel is a compact loop spanning 1 to 2 months from application to offer:

1. Apply on oldmissioncapital.com/careers. Find the relevant University program listing and submit through Greenhouse. Apply the day the posting goes live. The window is roughly 4 to 5 weeks and may close earlier if filled.

2. Resume screening. Applications are reviewed, likely on a rolling basis. Some candidates report being rejected at this stage before receiving an OA, suggesting active early screening. A strong CS background and 3.0+ GPA are the minimum bar.

3. HackerRank online assessment (60 to 90 minutes). Section 1: approximately 30 multiple-choice questions on CS fundamentals (data structures, algorithms, C++, Python, OOP, systems concepts) in 60 minutes. Section 2: 2 coding problems rated medium to hard. Candidates describe this as one of the hardest OAs in the industry.

4. Phone/video interview (30 to 60 minutes). For SWE: technical CS questions, potentially DSA or language-specific (C++, Python, OS, threading). For quant trading: mental math, probability questions, and brainteasers.

5. Final round / onsite (~2 hours, in-person). Multiple back-to-back interviews at Old Mission's Chicago office with traders and engineers. SWE candidates face systems design, coding, and low-level programming. Quant candidates face advanced probability, market-making scenarios, and trading simulations. Expect to meet senior team members given the flat hierarchy.

6. Offer decision. Offers extended on a rolling basis. The natural conversion path is the full-time Graduate Program (February or August start, $175K to $200K+ base).

So the two skills to drill are clear: deep CS fundamentals for the HackerRank OA (data structures, algorithms, C++, Python, OOP, and systems concepts at a level candidates call the hardest they have seen), and genuine comfort with low-latency systems thinking for the onsite. For quant trading candidates, add probability, brainteasers, and mental math to the drill list. And note: Old Mission does not accept unsolicited resumes from staffing firms without signed agreements, so apply directly through their careers page.

What Students on Reddit Say

Three community threads show the process from the inside, all paraphrased.

How Do You Stand Out at a Firm That Takes Single-Digit Interns?

Three moves, all before the mid-August close. First, apply the day the posting goes live: Old Mission's window is 4 to 5 weeks, the firm runs small cohorts, and Reddit reports candidates being rejected before even completing their OA. Every day you wait is a day closer to a closed posting. Second, prepare for the HackerRank OA like it is a final exam: candidates consistently describe it as the hardest they have encountered. Drill CS fundamentals (data structures, algorithms, C++, Python, OOP, systems concepts) and LeetCode mediums-to-hards, especially problems involving low-level memory management and systems design. Third, bring C++ depth, not breadth. Old Mission is a C++ shop building trading applications, so demonstrating real systems-programming projects in C++ carries more weight than a portfolio spread across five languages. And remember: at a 200-person firm where founders sit on the trading floor, culture fit matters intensely. Show intellectual curiosity, collaborative instinct, and genuine interest in how software drives trading.

What Other Companies Should You Consider?

Old Mission is not the only quantitative trading firm hiring interns on a summer timeline. If you are building a quant-internship list, these are the obvious neighbors:

Our finance internships summer 2027 guide maps the whole landscape, timeline by timeline.

FAQ

When do Old Mission internship applications open for summer 2027?

The 2027 SWE internship application opened in mid-July 2026 (university portals show July 13 to 15 posting dates). The window is expected to close by mid-August 2026 or when positions are filled. This is a narrow 4- to 5-week window, so apply immediately.

Is Old Mission internship hiring rolling?

Likely yes. Old Mission does not publicly state a rolling policy, but Reddit reports candidates being rejected before completing their OA, suggesting continuous screening. The narrow window and small cohorts reward early applicants. Apply as soon as the posting goes live.

How much does an Old Mission internship pay?

The SWE internship pays $150,000 to $200,000 annualized ($2,885 to $3,846 per week). The Quant Trader micro-internship pays $2,500 per week (~$130K annualized). Both include free corporate housing and daily breakfast and lunch. Glassdoor's employer-provided range is $175K to $250K per year for intern roles.

Does Old Mission sponsor visas for interns?

Yes. Ellis.com data shows Old Mission has filed H-1B visa sponsorship with a median salary of $162,500, suggesting the firm is open to international students. This is a notable difference from many traditional finance firms.

What is the Old Mission internship interview process like?

You apply through Greenhouse, pass a resume screen, then complete a HackerRank OA (30 MCQs on CS fundamentals plus 2 coding problems, rated one of the hardest in the industry). If you advance, there is a phone/video interview and a final 2-hour in-person onsite at the Chicago office. Total process: 1 to 2 months.

Do I need finance experience for an Old Mission SWE internship?

No. The job posting explicitly states finance experience is not required. However, a genuine interest in financial markets and understanding how software drives trading is valued. The technical bar is set by your CS fundamentals and C++ depth, not your finance knowledge.

Does Old Mission provide housing for interns?

Yes. Both the summer SWE internship and the winter Quant Trader micro-internship include corporate housing provided at no cost, plus free daily breakfast and lunch.

How does Old Mission compare to Jane Street, Citadel, or Two Sigma?

Old Mission is smaller (~200 employees) and less publicly recognized, but it is well-respected in the prop trading world. Compensation is competitive with top firms. The culture is described as very trader-led with a flat hierarchy where founders remain on the trading floor. The smaller size is an advantage for mentorship and direct impact. Glassdoor gives Old Mission a 4.2 out of 5 rating with 97% recommending the company.

Old Mission's application window closes in weeks, not months. Spend the runway building proof: a remote Externship turns 'interested in quantitative trading' into a finished systems-level project you can point at before the posting closes.