SIG (Susquehanna)

Large Enterprises

Most of these SIG (Susquehanna) write-ups come from Software Engineers (51), then Data Scientists (12). The most reported rounds are the technical phone screen (56), the system design round (3), the online assessment (1) and the onsite coding round (1).

63 interview notes · updated Sep 2026

SIG (Susquehanna)·Data Scientist·Technical Phone Screen

Jul 2026

SIG probability question for a Data Scientist role. One problem, no fluff, just math under pressure.

A bakery has 2 muffins left and 5 customers still in line. Each customer independently buys a muffin with 30% probability and a croissant with 70%. What is the probability that the muffins don't run out before everyone is served?

“This one took me longer than it should have.”

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SIG (Susquehanna)·Data Scientist·Technical Phone Screen

Jul 2026

SQL-heavy technical screen for a data scientist role at SIG. Six questions back to back, all analytics SQL, no behavioral fluff. The problems ranged from basic conversion funnels to some genuinely tricky window function and cross-join completeness stuff.

For a fixed 7-day window, compute conversion rate (delivered / created) broken down by city and courier type. An order counts as delivered if status is 'delivered' and delivered_at is not null, regardless of when it was delivered.
Generate a monthly volume report for the last 3 months showing orders created, orders delivered, and GMV (delivered count times a fixed rate) per courier type. Months with zero activity must still appear in the output.
For each user, find the first streak of 3 consecutive delivered biker orders. Any non-biker delivery breaks the streak; non-delivered orders are ignored entirely. Return the first and third order IDs and the time span between them in minutes.
Compute the 95th percentile delivery time in minutes for delivered orders created in the last 30 days, grouped by courier type. Also return the count per group.
Extend the monthly volume report to include city as a dimension, ensuring every combination of city (from both users and couriers), courier type, and month appears in the output even with zero orders.
Find all orders created on or before a cutoff timestamp that were not delivered within 2 hours of creation. Include orders where delivered_at is null or where it exceeds the 2-hour threshold. Return a boolean column flagging these stale orders.

“Straightforward on the surface but the 'regardless of when delivered' part tripped me up briefly.”

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SIG (Susquehanna)·Data Scientist·Technical Phone Screen

Jul 2026

A probability brain teaser from SIG for a Data Scientist role. Just the one question from what I can tell, classic quant-style stuff you'd expect from a trading firm.

Two flowers bloom independently. The purple flower starts blooming at a uniformly random time over the next 30 days and stays in bloom for 9 days. The red flower also starts at a uniformly random time over the same 30-day window and stays in bloom for 12 days. What is the probability that they overlap in bloom at some point?

“This is a geometric probability problem.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jul 2026

Quant researcher screen at Sig with a river/canoe word problem that looks like a simple distance-rate question until you realize you have to figure out the departure time working backwards from an arrival constraint. Pretty classic SIG-style brainteaser energy.

Two friends paddle upstream for 4 hours, then turn around and go downstream for 5 hours to reach their campsite. The next day they paddle back to the original starting point, which is 23 miles upstream, arriving at 6pm. The river current is always 2 mph and they paddle at a constant speed in still water. What time did they leave that morning?

“I set up the algebra fine but kept second-guessing whether the 23 miles was net displacement or total distance traveled.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jul 2026

SIG quant engineer interview with a classic knights and knaves logic puzzle. Short and sharp, felt more like a screening than a deep technical round.

On an island where knights always tell the truth and knaves always lie, person B makes two statements: 'A and I are the same type' and 'A always lies.' What type is each person?

“I stared at this for a second because both statements together create a contradiction if you assume B is a knight.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jun 2026

SIG quant engineer interview with a probability and statistics question pulled straight from a contingency table setup. Pretty focused, no fluff.

You're given a two-way contingency table from a survey of 1000 people, with exercise preference on one axis and age group on the other. How do you compute the conditional probability that a respondent is in the 33-37 age group, given that their preferred exercise is swimming?

“Pretty mechanical once you see it.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jun 2026

Posted this looking for intel on SIG's trading system engineering internship pipeline. Recruiter call was relaxed, just some light motivation questions and a basic probability problem. Now prepping for a live C++ coding round and not totally sure what to expect.

Why are you interested in this role and company?
A basic probability question during the recruiter screen.

“Pretty standard opener, recruiter was casual about it.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jun 2026

SIG coding round, one algorithmic problem focused on subarray counting with a zero-parity twist. Pretty clean problem once you see the pattern, but getting there under pressure is a different story.

Given an integer array, how many contiguous subarrays contain an odd number of zeros? Solve it in O(n) time and explain your approach and complexity.

“I stared at the example for longer than I should have.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jun 2026

Sig SWE interview centered on implementing a custom vector from scratch, which sounds manageable until you realize they care deeply about every layer of memory management. Three distinct parts, each peeling back another level of C++ internals.

Implement the core memory model for a custom vector: define the data members, write raw allocation using operator new, implement reserve, and add push_back with geometric capacity growth. Allocation and construction must be kept separate.
Implement the Rule of Five for your custom vector: destructor, copy constructor, copy assignment, move constructor, and move assignment, ensuring deep copy semantics and O(1) moves.
How do you make the destructor and reallocation logic correct when T's constructors or move constructors can throw? Specifically, how do you avoid leaking or corrupting the container mid-reallocation?
Why might a 1.5x growth factor be preferable to 2x for a general-purpose allocator?
How would you add emplace_back with perfect forwarding, and what does it gain over push_back?
What are the iterator and reference invalidation rules on reallocation, and how would that affect the API contract for your vector?
How would adding an Allocator template parameter change where construction and destruction happen in your vector implementation?

“The separation of allocation from construction is where I expected to trip up and I kind of did.”

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SIG (Susquehanna)·Software Engineer·Technical Phone Screen

Jun 2026

SIG quant researcher interview with a combinatorics path-counting problem that looks straightforward until you actually try to count it. The constraint makes it way harder than a standard grid walk.

A frog moves from (0,0) to (4,6) on a grid, taking steps either right or up one unit at a time. It cannot take three consecutive steps in the same direction. How many valid paths exist?

“My first instinct was to just write out the recursion and I kept second-guessing my base cases.”

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SIG (Susquehanna) interview FAQ

What rounds are in the SIG (Susquehanna) interview?

Candidates most often report a technical phone screen (56 write-ups), a system design round (3), an online assessment (1) and an onsite coding round (1).

What does the SIG (Susquehanna) technical phone screen cover?

Across 56 technical phone screen write-ups, the most tagged question topics are Algorithms & Data Structures (61 questions), Technical Trade-offs (44) and Product Analytics & Metrics (13).