NK Securities Interview Guide (2026): CP Screens, Brainstellar Puzzles, and Crore-Level Campus Offers

NK Securities Research is an Indian high-frequency trading firm founded in 2011 and headquartered in Gurugram, with a growing international footprint that includes Singapore. It builds and runs its own low-latency trading systems, and most of that infrastructure is C++. That single fact shapes the whole interview: the firm screens for raw algorithmic speed, probabilistic reasoning under time pressure, and C++ depth, because those are the skills the desk actually uses. Finance knowledge is explicitly not required; the firm assesses technical ability and fit, and teaches the markets side after you join. Glassdoor candidates rate the research intern and quantitative analyst interviews as the firm’s hardest, so treat this as a top-tier quant loop, not a services-company screen.

Process

The loop starts with an online assessment. Campus candidates report a test with around 8 to 9 MCQs covering probability, expected value, operating systems, and computer networks, plus 2 DSA problems in the competitive-programming style. The firm has said the test leans on C++ deliberately, since its trading stack runs on it. Lateral candidates apply through the careers page (hiring runs on Greenhouse) and see a similar technical bar. The firm also runs side channels into the same pipeline: a QuantFest hiring event and a hackathon with problems set by internal quant, trading, and engineering teams.

After the test, most candidates report two technical interviews. Round one mixes basic puzzles with CP and software questions; round two moves to medium-to-hard puzzles, with probability questions in the Brainstellar style, algorithm discussions, and C++ theory. Multiple candidates note the interviewers are friendly and will nudge you with hints if you stall, which means verbal reasoning matters as much as the final answer. A final HR and culture-fit conversation checks motivation and alignment. Glassdoor data puts the average quantitative researcher process at about 29 days end to end; campus loops compress into placement-season timelines, sometimes with an offer the same day the interviews finish.

What they actually ask

• Competitive-programming DSA, typically 2 problems on the online test and more in interviews. One reported problem: given n piles of stones where merging two consecutive piles costs their combined total, find the minimum cost to merge everything into one pile (classic interval DP).
• Probability and expected-value puzzles, often lifted from or resembling Brainstellar. One reported interview puzzle: two friends draw cards from a shuffled deck and must guess each other’s cards, designing a strategy to maximize the minimum probability of success.
• C++ internals and OOP theory: constructors and destructors, pointers, memory behavior, and performance-oriented C++. The firm has stated outright that the assessment focuses on C++ because the trading infrastructure runs on it.
• OS and networking MCQs on the online test: scheduling, memory, and core networking concepts at solid undergrad-course level rather than kernel trivia.
• Brainteasers and strategy puzzles that escalate in difficulty from round one to round two, where partial progress plus clear reasoning can still pass if you use the interviewer’s hints well.
• Mental math and quick estimation woven into the probability rounds; reports do not describe a separate dedicated mental-math round, so expect it inside the puzzle discussions instead.

Levels and comp (2026)

NK Securities pays at the top of the Indian fresher market, and the numbers circulating are strong but should be read as reported figures, not guarantees. A widely shared IIT Bombay campus breakdown for an SDE 1 offer lists 46 lakh base, 18 lakh fixed bonus, 2 lakh joining bonus, 6 lakh in allowances, and a performance bonus of up to 100 percent of fixed pay, for a total between roughly 72 lakh and 1.38 crore INR. Another reported structure cites a 54 lakh base with bonuses that can exceed 100 percent. Levels.fyi shows software engineer total comp in India averaging about 69 to 98 lakh, and Glassdoor’s 68 salary reports put typical software engineer and quantitative researcher figures around 80 to 81 lakh. Claims of multi-crore payouts for top performers show up in placement chatter and are plausible given the bonus structure, but there is no public dataset that confirms them, so hedge accordingly. Campus hiring through IITs and similar schools is the main intake; lateral roles exist for quant researchers, C++ developers, and infrastructure engineers, and the lateral bar mirrors the campus loop with more weight on prior low-latency or systems work.

Prep priorities

Put most of your hours into two buckets. First, competitive programming: Codeforces Div 2 C/D level, interval and classic DP, greedy proofs, and clean implementation speed, since the online test filters hard on this. Work through our coding interview archive and the coding patterns cheat sheet to organize your practice. Second, probability: finish Brainstellar end to end, add expected-value and conditional-probability drills, and practice explaining solutions aloud, because the interviews are conversational and hint-driven. Then layer in C++ depth (object lifetime, virtual dispatch, pointers, move semantics, what costs what at runtime) and a fast review of OS and networking fundamentals for the MCQs. System design in the web-services sense rarely appears at this level, though skimming latency-oriented material in our system design section helps you talk about performance credibly. For the HR round, have a plain answer for why HFT and why you can sustain the pace; the standard behavioral prep applies.

Frequently Asked Questions

Do I need a finance background to get hired? No. The firm states that finance and trading knowledge are not prerequisites; it hires on technical skill and problem-solving, then trains new joiners with a mentor from the core team. Every reported interview stays on math, code, and systems.

How hard is the online test compared to other HFT firms? Reports place it in the same band as other Indian prop firms: 2 CP problems plus MCQs on probability, OS, networking, and C++. Candidates who are comfortable at Codeforces Div 2 C level and have covered undergrad OS and networking describe it as demanding but fair.

What is the work culture actually like? Mixed, and the sample is small. Glassdoor shows a 3.1 overall rating across 46 reviews, with compensation rated 4.4 but work-life balance at 2.9 and culture at 2.6; 47 percent would recommend the firm. Reviews mention long hours, which is consistent with HFT generally. Attrition data specific to the firm is thin, so weigh the pay against the pace with open eyes.

Can non-IIT candidates get in? Yes, though the campus pipeline skews heavily toward IITs and similar schools. The QuantFest event, the hackathon, and direct applications through the Greenhouse careers portal are open routes; a strong competitive-programming record (high Codeforces or ICPC results) is the most reliable signal for getting a lateral or off-campus look.