BMLL hasadded Five Rings, a New York proprietary trading firm, to the advisory board ituses to shape its product roadmap, the market data company said today (Thursday).The move puts a second prop firm on a panel that already counts some of thebiggest names in institutional finance.Five Ringsjoins the Client Product Advisory Board alongside Berenberg, Kepler Cheuvreux,Norges Bank Investment Management, Optiver, Rothschild & Co Redburn, StateStreet Global Advisors and Stifel. BMLL said the firm trades across asset classes andleans on detailed historical data to test ideas and refine its quantitativeresearch."BMLL'shigh-quality data and research environment have become instrumental," ParkerLim, head of special projects at Five Rings, added in a statement.A Client Board ThatDoubles as a Sales ToolBMLLlaunched the advisory board in February 2025 and uses it to gather feedback ondata standards, delivery formats and coverage gaps. The companyhas turned that input into product, releasing its Trades Plus execution analyticsdataset lastSeptember as the first tool built directly from board members' requests.One member,Optiver, sits on both sides of the table. The Amsterdam market maker is aminority shareholder in BMLL andled a $21 million investment in the company in October 2024, which means apart-owner now shares an advisory forum with a competing prop firm.PaulHumphrey, BMLL's chief executive, said the company was "delighted towelcome a highly sophisticated firm like Five Rings to the community."BMLL did not disclose commercial terms or say whether Five Rings is a payingclient.Crowded Market forGranular Historical DataBMLL, whichdescribes itself as an independent provider of harmonized Level 3, 2 and 1historical order book data, competes in a segment that has drawn both startupsand exchange groups. Its pitchis that clients can rent curated, normalized data rather than buy and clean itthemselves.Rivals arepushing on the same workflows. Databento sells nanosecond-precision datathrough cloud-delivered APIs and added a Databricks integration in 2024, whileKaiko has built similar distribution for digital asset order book records. Exchangeoperators including Nasdaq and CME Group have moved more of their historicalcontent into cloud marketplaces, in some cases bundled with their ownanalytics.BMLL hasanswered by stacking distribution deals and partner content on top of its coredataset. In April it plugged its data into Databricks, and it has layered third-partyoptions analytics onto its own records to widen coverage without buildingeverything in house.Nordic Capital Pushes aCommercial BuildoutTheadvisory board addition lands during a busy stretch for the company, whichNordic Capital acquired in October 2025 in a deal struck alongside Optiver.Since then the London-based firm has stepped up hiring and product work.In April itdisclosed nine new hires across partnerships, sales, revenueoperations, finance and engineering, and days later added SpiderRock's US options data to its research environment. In March itopened a year-long pilot with Tradefeedr to extend transaction cost analysisfrom foreign exchange into equities and futures.Optionsdata has been a particular focus. BMLL first launched six years ofnanosecond OPRA records in November 2024, and the company now says it offers more thanseven years, sitting alongside its US equity and futures datasets.This article was written by Damian Chmiel at www.financemagnates.com.