C

Citadel Securities

Global market maker delivering liquidity

Quantitative Researcher Engineer – PhD Intern - Europe

Summer 2026Updated
No salary listed
Internship
PhD
London, UK
In Person
Quantitative FinanceQuantitative Trading / Algorithm Development

About the job

Requirements
  • PhD degree in computer science, mathematics, statistics, physics, or another highly quantitative field
  • Strong programming skills with proficiency in one or more programming languages, including C++, Python, and R
  • A deep passion for technology, software development, and mathematics
  • Strong computer science fundamentals and software development experience
  • Experience with some of the following areas: Distributed Computing, Natural Language Processing, Machine Learning, Platform Development, Networking, System Design, and/or Web Development
  • Proven track record of creatively solving problems by understanding and prioritizing business value and applying technology solutions
  • Strong written and verbal communications skills
Responsibilities
  • Design, develop, test, and deploy elegant software solutions for automated trading systems
  • Partner with the Quantitative Research team to define priorities and deliver custom software solutions

About the company

Citadel Securities is a global market maker that provides liquidity and trading services to institutional clients in equities, options, and FICC markets. It uses advanced technology and data analytics to place and manage bid-ask quotes, execute trades, and optimize order routing, earning a small margin on each trade and charging fees for services. Its products and services help clients meet liquidity needs with low-cost, efficient execution. The company distinguishes itself by aiming for the fairest, most transparent, and open markets, continually reinvesting in technology and expertise to improve market efficiency and transparency. The goal is to bridge the financial markets with the real economy by creating reliable liquidity and transparent trading environments.

Company Size

1,001-5,000

Company Stage

Growth Equity (Venture Capital)

Total Funding

$1.2B

Headquarters

Miami, FL

Founded

2002

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Simplify's Take

What believers are saying

  • Second-quarter 2026 trading revenue hit $7.3 billion, with net income at $3.3 billion.
  • October 2, 2026 Wolfe partnership expands institutional flow and adds research capabilities.
  • DTCC tokenization production and Fireblocks support open new collateral and digital-asset revenue streams.

What critics are saying

  • June 29, 2026 spoofing suit against Citadel Securities and Virtu threatens costly discovery.
  • SEC scrutiny over CAT funding and order-mismarking history keeps compliance pressure persistent.
  • If retail flow and block-trading growth fade, 2026 revenue momentum collapses fast.

What makes Citadel Securities unique

  • Citadel Securities pairs market making with Wolfe Research distribution after October 2, 2026.
  • It spans equities, options, FICC, and tokenization workflows through DTCC and Fireblocks.
  • Its scale handles over one-third of U.S. retail stock trades, strengthening liquidity network effects.

Help us improve and share your feedback! Did you find this helpful?

Benefits

  • Health Insurance
  • Life Insurance
  • 401(k) Retirement Plan
  • Performance Bonus

Growth & Insights and Company News

6 month growth

1%

1 year growth

1%

2 year growth

0%
Flywheel Publishing, LLC
Oct 29th, 2026
DTCC launched tokenization on Canton with Ondo as a partner. Which coin benefits more?

DTCC launched tokenization on Canton with Ondo as a partner. Which coin benefits more? DTCC just launched a tokenization service backed by Fidelity, JPMorgan, and Bank of America, and both Canton Coin and Ondo landed spots in the rollout. But a closer look at how the service actually works reveals that neither coin may... This post may contain links from our sponsors and affiliates, and Flywheel Publishing may receive compensation for actions taken through them. Recently, Canton Coin (CC) and Ondo (ONDO) each secured a partnership with the Depository Trust & Clearing Corporation (DTCC), a leading U.S. securities firm. This partnership marks the rollout of DTCC's tokenization service, which went live on October 28, 2026. While DTCC is a major player, the question is which coin will ultimately benefit from this development. As of the latest updates, CC is trading at $0.0956, reflecting a 2.8% decrease over the past 24 hours and a total drop of 27.0% over the last month. Meanwhile, ONDO is priced at $0.4153, showing a modest increase of 0.7% in 24 hours but down 20.1% on a monthly basis. This raises an important question. Which of these coins is better positioned to gain traction from DTCC's tokenization push? DTCC's tokenization service launches with 34 securities on Canton. DTCC's new tokenization service initially includes 34 different securities, featuring selected large-cap stocks from the Russell 1000, various exchange-traded funds, and U.S. Treasuries. The tokenized versions maintain the same ownership rights and protections as their traditional counterparts, allowing investors to easily switch between the two forms and transfer tokens to their own digital wallets. This service operates on two networks, the Canton Network and DTCC's private Besu network. DTCC plans to broaden its blockchain reach in 2027 and has already partnered with 20 notable participants such as Citadel Securities, Fidelity Investments, Edward Jones, Bank of America, and JPMorgan Chase, alongside infrastructure providers like BitGo Bank & Trust, Fireblocks, DRW, Blockdaemon, and Ondo. DTCC's president and chief executive, Frank La Salla, stated that the launch is the culmination of years of development. The groundwork goes back to December 2025, when the SEC issued a no-action letter to DTCC's clearing unit, indicating that SEC staff would not pursue enforcement action if the service was implemented as planned. Input from over 150 firms helped shape the final design, with limited production trades conducted with more than 30 firms as early as July 2026. Lawmakers also moved on broader digital-asset rules around the same stretch, with the Senate's Crypto Clarity Act vote in September setting fresh ground rules for how tokens like these get treated. No requirement for either coin in the new service. Interestingly, DTCC did not specify a settlement asset for this launch, meaning there is no obligatory cryptocurrency tied to the service, including CC and ONDO. Instead, banks will receive tokenized securities directly into their digital wallets, and the announcement does not mandate any participant to hold, buy, or use either coin. Furthermore, DTCC runs a similar tokenization service on its private Besu network, which does not have a public token. This means that as DTCC expands in 2027, it could narrow Canton's current advantage before either coin establishes strong demand. Ondo's link to the new service appears to be the weaker of the two. Ondo describes its token, ONDO, as a governance token for both the Ondo DAO and Flux Finance, possessing a fixed supply of 10 billion tokens with no entitlement to fees generated from Ondo's products. SoFi Active Invest is offering a limited-time promotion. Open an account, fund it with $50 or more, and you could receive up to $1,000 in complimentary stock for Active Invest accounts. See for yourself by clicking here now. (Sponsor) Given that Ondo already lists tokenized U.S. stocks on Robinhood Markets' Robinhood Chain, with 15 tokenized stocks and funds available for 24/7 trading through Uniswap, the new DTCC service could introduce competition for Ondo's existing offerings unless it evolves to distribute DTCC's tokens. Canton Coin's fee structure offers a small advantage. Canton Coin is uniquely integrated into the network's fee system. Validators, the computers that process and confirm transactions, charge fees priced in U.S. dollars, but they pay in CC, burning the coins and removing them from circulation. In return, validators, Super Validators, and application providers mint new CC as rewards, creating a "burn-mint equilibrium" that keeps burned and newly minted coins in balance over time. However, this system has its limitations. Each validator receives a free traffic allowance before fees apply, and paid traffic costs are based on message size rather than transaction value, so a single large transaction could burn the same amount of CC as a much smaller one. Additionally, third parties can manage the burn process for validators, so a bank could use dollars to cover network traffic costs without ever handling CC directly. Ultimately, a token's price movement depends on monetary flows rather than partnership announcements alone. CC is trading 50.7% below its all-time high of $0.1942 in February 2026, reflecting a 37.4% year-to-date decline. ONDO, on the other hand, trades 80.6% below its December 2024 peak of $2.14, despite a 15.5% gain so far this year. Which coin will benefit more from DTCC's launch? In conclusion, Canton Coin has a slight edge in terms of potential benefits from the DTCC launch. Its direct connection to the Canton Network's fee structure positions it slightly better than Ondo, as the latter seems to have a less clear benefit from its association with DTCC's tokenization service. The bigger winners are the companies, not the coins. Digital Asset gains the largest reference customer in U.S. post-trade, and Ondo Finance gains a seat beside Wall Street's largest custodians. For CC, the edge becomes demand only if banks burn more coins than validators mint; for ONDO, the clearer path is through its own DAO voting to tie the token to Ondo's revenue. Want up to $3,000 in stock? SoFi is giving new Active Invest users complimentary stock. Looking to grow your money but unsure where to begin? SoFi Active Invest is offering a limited-time promotion; open a new Active Invest account, fund it with $50 or more, and you could receive up to $1,000 in complimentary stock. From $0 commission trading3 to fractional shares4 and automated investing, this app is designed to simplify investing for everyone, whether you're just starting or already experienced. Its easy to sign up and secure your bonus. (Sponsor) 1 INVESTMENTS ARE NOT FDIC INSURED - ARE NOT BANK GUARANTEED - MAY LOSE VALUE Brokerage and Active investing products offered through SoFi Securities LLC, member FINRA( www.finra.org )/SIPC( www.sipc.org ).2The probability of a member receiving $1,000 is 0.028%. If you don't make a selection in 45 days, you'll no longer qualify for the promo. Members must fund their account with a minimum of $50.00 to qualify. The probability percentage is subject to decrease. Members are only eligible for the Stock Award promotion upon opening their first brokerage account; subsequent cash brokerage accounts are ineligible for the promo, including for members with multiple accounts. 3Other fees, such as exchange fees, may apply. Please view our fee disclosure to view a full listing of fees. 4There are limitations with fractional shares to consider before investing. During market hours fractional share orders are transmitted immediately in the order received. There may be system delays from receipt of your order until execution and market conditions may adversely impact execution prices. Outside of market hours orders are received on a not held basis and will be aggregated for each security then executed in the morning trade window of the next business day at market open. Share will be delivered at an average price received for executing the securities through a single batched order. Fractional shares may not be transferred to another firm. Fractional shares will be sold when a transfer or closure request is initiated. Please consider that selling securities is a taxable event. Sam Daodu is a crypto analyst and the editor of 24/7 Wall St.'s Crypto Desk, where he covers Bitcoin, XRP, Ethereum, Solana and the altcoins investors search for most. His work focuses on price levels, spot ETF flows, on-chain data and the regulatory decisions that move crypto markets, written so a first-time buyer and a seasoned trader can both use it. Sam has written about crypto professionally since 2019 and has published more than 2,000 articles. Before joining 24/7 Wall St., he wrote for crypto media outlets and Web3 companies and ghostwrote for crypto founders and token launches. His analysis is syndicated on Yahoo Finance, MSN and AOL and has been cited by other crypto news sites. He also founded MacLabs Marketing, a content and personal branding agency for crypto founders and executives. When he isn't reading charts, Sam is usually at the gym or watching One Piece, a series he maintains has better tokenomics than most altcoins.

eFinancialCareers
Oct 22nd, 2026
The ex-Citadel Securities and Tower Research traders that left for fintech don't want to stop trading.

The ex-Citadel Securities and Tower Research traders that left for fintech don't want to stop trading. 22 October 2026 Having your quantitative cake and eating it too. You can take a quant out of trading but you can't take trading away from the quant. The electronic trading industry is a rich source of talent for startups, and some of the traders currently working in fintech startups have been building out quant trading functions within their companies. Take Mark Wilkinson, Citadel Securities' former head of FICC systematic trading, who left for investment platform WealthSimple. He announced via LinkedIn yesterday that he's "building out a quantitative trading function" at the fintech; job listings state that the quant traders hired will conduct research and build algorithms "to produce an edge for our clients and the company." Wilkinson is looking for people with at least three years in quant trading for the buildout. He's not alone. Annanay Kapila, an ex-Tower Research trader and founder of perpetuals exchange QFEX, told us that his firm has begun "open-sourcing some mid-frequency trading strategies to some of our clients." He announced last week on LinkedIn that, in the first 12 days of October, QFEX made more money than it did for the 12 months ending August 2026. He said the firm's trading strategies benefitted greatly from the release of OpenAI's Astra model in early September: "I've never seen any model be able to do quant research as well as Astra." More QaaS (Quant as a Service) startups may be birthed if more ex-traders get backed. Alexandr Wang, chief AI officer of Meta, was famously part of Hudson River Trading's first intern class; he said on a recent podcast that he spoke to HRT's founder (presumably Jason Carroll) and advised him to "just invest in all the interns... give all the interns seed checks." Have a confidential story, tip, or comment you'd like to share? Contact: WhatsApp: http://wa.me/442079977910 (+44 20 7997 7910), Telegram: @AlexMcMurray, Signal: @AlexMcMurrayEFC.88 Click here to fill in our anonymous form, or email [email protected]. Bear with us if you leave a comment at the bottom of this article: comments are moderated intermittently by human beings. Sometimes these humans might be asleep, or away from their desks, so it may take a while for your comment to appear. You must take sole responsibility for comments you post on this site. We will take reasonable steps to weed out anything that we consider to be offensive or inappropriate. The essential daily roundup of news and analysis read by everyone from senior bankers and traders to new recruits. Boost your career. Find thousands of job opportunities by signing up to eFinancialCareers today.

Bloomberg Law
Oct 20th, 2026
ASI raises $325M at $3B valuation in Spark-led round for AI that manages military and airline assets

ASI, a Boston-based startup previously known as Air Space Intelligence Inc., raised $325 million in a series C round that values it at $3 billion. Spark Capital led the round. Craft Ventures, Andreessen Horowitz, and affiliates of Citadel Securities, among others, also took part. The company is due to announce the deal Tuesday. ASI will use the money to expand its artificial intelligence system, which helps the military, airlines, and air-traffic controllers manage assets. The company is part of a resurgence in US defence and aerospace technology startups, which have drawn growing interest from investors and government agencies.

Bloomberg
Oct 20th, 2026
What to expect from spacex earnings.

What to expect from spacex earnings. Oct 20th, 2026 Citadel Looking to Grow in Fixed Income, Esposito Says "We're only really getting started in fixed income," Citadel Securities President Jim Esposito says during an interview with Bloomberg's Dani Burger on the sidelines of Citadel's annual Future of Global Markets Conference in New York. Esposito also says the firm is "maniacally" focused on market making. Top video. Available on:

eFinancialCareers
Oct 16th, 2026
Citadel Securities hired Aditya Singh from Balyasny.

Citadel Securities hired Aditya Singh from Balyasny. 39 minutes ago Last week reported that ex-Goldman Sachs rates trader Aditya Singh had left Balyasny Asset Management. Today, we can report that Singh is joining Citadel Securities. Citadel Securities didn't respond to a request to comment on Singh's arrival when asked multiple times last week. We understand that he will be supporting the rates team. Singh is understood be joining the team run by Nikhil Choraria, another Citadel Securities hire from Goldman Sachs. Initially we were given to understand that Citadel Securities had not hired Choraria, but Choraria arrived there in September and is running the fixed income business. It's thought that Singh resigned from Balyasny before the recent spate of exits at the fund, possibly departing in May. Balyasny declined to comment previously on his departure. Citadel Securities employs a cluster of Goldman's ex-macro people in London. As well as Choraria and Singh, it employs Nohshad Shah, Frank Flight and Ishaan Sethi. Citadel Securities declined to comment. Follow me on X. Follow me on LinkedIn. Have a confidential story, tip, or comment you'd like to share? Contact: +44 7537 182250 (SMS, Whatsapp or voicemail). Telegram: @SarahButcher. Signal: sarahbutcher.22 Click here to fill in our anonymous form, or email [email protected]. Bear with us if you leave a comment at the bottom of this article: comments are moderated intermittently by human beings. Sometimes these humans might be asleep, or away from their desks, so it may take a while for your comment to appear. You must take sole responsibility for comments you post on this site. We will take reasonable steps to weed out anything that we consider to be offensive or inappropriate. The essential daily roundup of news and analysis read by everyone from senior bankers and traders to new recruits. Boost your career. Find thousands of job opportunities by signing up to eFinancialCareers today. Top Articles

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