21X has appointed Ray Tierney CEO of 21X LLC as the tokenized-securities market-infrastructure provider looks to establish a U.S. broker-dealer operating an alternative trading system. The move headlines a week of personnel changes that touches prediction markets, tokenized products, securities services and prime brokerage across the Street.

Tierney previously served as CEO of Broadridge Trading and Connectivity Solutions following its acquisition of Itiviti, and earlier was global CEO of Trading Solutions at Bloomberg. He will lead 21X's U.S. expansion as the company seeks regulatory approval for an ATS supporting blockchain-based issuance, trading and settlement of tokenized securities. The appointment brings a veteran of electronic trading and market technology to 21X as it makes its first expansion outside Europe.

Polymarket Targets Institutional Flow

Polymarket has named former Goldman Sachs partner Lisa Mantil head of Institutional Growth, putting her in charge of building the prediction market's business with investment managers, trading firms, corporates and banks. Mantil joins after nearly three decades at Goldman, where she was named partner in 2018 and most recently built and led the firm's ETF Accelerator.

In her new role, she will focus on developing the products, infrastructure and liquidity needed to expand institutional participation in prediction markets. The hire gives Polymarket a veteran of institutional product development as it looks to push prediction markets further into mainstream investment and risk-management strategies.

Broadridge Creates Tokenized Product Role

Theo Golden has joined Broadridge as head of Tokenized Product, International, a newly created role spanning capital markets, funds and other tokenized assets. Golden moves from Baillie Gifford, where they served as head of Digital Assets and helped build the asset manager's digital-asset strategy and operating model.

Golden also launched Baillie Gifford Enhanced Yield, described as the UK's first fully native tokenized fund, and previously co-managed the firm's Strategic Bond Fund. At Broadridge, Golden will work with clients on tokenized products while also supporting M&A and strategic venture investments in digital assets — a signal that the post-trade vendor sees tokenization as both a product line and an acquisition target set.

State Street Consolidates Execution Under One Executive

State Street has put Taryn Siglain in charge of its newly combined Execution, Financing and Clearing business, bringing high-touch and electronic execution, agency lending, prime services, secured financing and clearing under one organization. Siglain, an executive vice president at State Street Markets, previously served as global head of Prime Services after joining the firm in 2023.

Before State Street, she spent 15 years at Morgan Stanley across securities finance, investor relations, corporate treasury and accounting policy. Her expanded mandate puts a broad swath of State Street's institutional trading and financing businesses under a single executive — a structural choice buy-side desks will watch for its implications on bundled execution and financing pricing.

HSBC Builds Out EMEA Securities Services Sales

HSBC has hired Fiona Neville as head of Securities Services Sales for Europe and the Middle East, based in London. Neville joins from Deutsche Bank, where she was head of Securities Services, Europe, and will lead HSBC's EMEA sales organization with a focus on winning new mandates. She brings more than 20 years of financial-services experience to the role.

Pirum Pushes Deeper into French-Speaking Europe

Stephan Sanner has joined Pirum as senior sales executive, charged with expanding the firm's securities-finance automation, connectivity and AI-enabled solutions across French-speaking Europe. Sanner brings 25 years of capital-markets experience, including previous roles at EquiLend, TMX Group, NYSE Euronext/SecFinex, Bloomberg and Pertrac Financial Solutions. He joins most recently from DXB Pump & Power, where he served as commercial director for Europe.

Buy Side and Sell Side Add Desk Talent

APG Asset Management has promoted Christos Saltapidas to quantitative fixed-income trader in Amsterdam, where he will trade government bonds and interest-rate derivatives. Saltapidas has spent six years at APG and moves to the trading desk after four years as a systematic commodities portfolio manager and quantitative researcher. He joined the asset manager in 2020 as a junior asset-management professional, rotating through quantitative, research and portfolio-management teams, and previously worked at NN Investment Partners.

Hudson River Trading has hired Matt O'Neill as an investor with HRT Ventures in London. O'Neill joins from Flow Traders, where he spent three years as global head of business development working with banks and on venture-capital initiatives. Before that, he spent 14 years across two stints at Goldman Sachs, including as a managing director in Principal Strategic Investments, and five years in Morgan Stanley's equities-clearing business. At HRT Ventures, O'Neill will focus on early-stage companies operating across capital markets, trading and the broader financial ecosystem.

Gary Hughes has joined BNY as an equity sales trader in Dublin, working within the bank's European fixed-income and equities trading team and covering both asset classes. Hughes moves from Comgest, where he spent roughly a decade and most recently worked as a trader after initially joining the asset manager in a middle-office role. Earlier in his career, he spent three years at State Street. His arrival comes as BNY continues to build out its equities operation following the appointment of Bianca Gould as global head of equities.

Advisory and Prime Services

Bennett Schachter has joined Centerview Partners as a partner to lead the investment bank's capital-advisory business across public and private markets. He moves from Elliott Investment Management, where he spent four years as a managing director focused on capital-markets and financing solutions. Before Elliott, Schachter spent 25 years in investment banking, including senior roles at Morgan Stanley and Goldman Sachs, and led alternative and capital solutions at Morgan Stanley. His appointment comes as Centerview expands its work across strategic financing, private capital and alternative funding solutions.

Marex has added Tom Tardif to its global capital introduction team within Prime Services, which connects hedge-fund managers with institutional investors and supports Marex's broader prime-brokerage offering. Tardif's exact title and previous employer were not disclosed. The hire comes as Marex continues to expand its institutional prime-services business.

The common thread across the week's moves: firms are staffing for tokenized market infrastructure, institutional prediction markets and consolidated execution-financing models — hires that will shape vendor, venue and counterparty choices for desks on both sides of the market in the year ahead.