Merger control is a calendar. The hire is a question of when.

We have worked the Brussels in-house market for 5 years, for general counsel and chief legal officers at serial acquirers and at groups whose deals now clear three regimes at once. Over the trailing three years the typical timeline on this line has been 4 to 7 months. The completion rate on the closed files is 93 percent.

Of 15 closed Brussels in-house searches over those three years, 8 were filing-manager seats at serial acquirers in technology, life sciences or healthcare — mid-to-senior counsel who would own Form CO timing, the CMA briefing paper and the HSR overlap assessment under a general counsel or associate general counsel. The other seven were broader competition, compliance or corporate seats that touched a filing only as an episode. That split is the buy line in our own book.

A chief legal officer at a listed life-sciences group, Brussels-facing, put the test to us in one sentence: the weeks they bought were the ones before the Form CO went in, not the ones after. Their corporate-development team now opens the economic-evidence pack at term-sheet, not at signing. A general counsel at a mid-market industrial who signs one concentration a decade told us the opposite, after a requisition that sat: they needed a panel, not a payroll line.

Sartori’s quarterly survey since 2019, read in the second-quarter 2026 wave against that same Brussels cohort, found that 52 of 61 general counsel and heads of legal at companies with a live M&A pipeline still rent the filing calendar rather than keep a standing in-house filing manager. That is not a failure of the market. It is the correct answer for every company on the one-deal side of the line, and it is the wrong answer for a serial acquirer that has already learned the cost of starting Form CO after the SPA is signed. Serial, on this desk, means a live pipeline that already clears two or three regimes in a single year — EUMR plus FSR, or HSR plus a CMA briefing paper — not a company that had one busy quarter and a frightened board. The head of legal who opens a standing requisition after a single Phase I scare is buying a seat the company will not know how to brief.

The 2025 capital cycle made the stack thicker, not the intervention rate higher. PwC’s 2026 outlook, on the LSEG announced-deal tape at 31 December 2025, recorded global deal values up 36 percent, about 600 transactions above $1 billion, and megadeals above $5 billion rising from 63 in 2024 to 111 in 2025, with values around $3.5 trillion. That is more SPAs landing on EUMR plus FSR plus CMA plus HSR at once. It is not a census of Phase II seats, and it is not a reason for a one-deal company to open a standing requisition.

A U.S.-listed global technology platform posted an Associate General Counsel, Competition & Regulatory seat in Washington whose first duty is counsel on antitrust issues relating to mergers and acquisitions and legal strategy on reviews by regulators around the world. The gates are a J.D. or foreign equivalent, membership in at least one U.S. state bar, and five or more years at a law firm, in government, or in-house on merger reviews. That is the shape of the seat: under the general counsel, on the global legal team, titled as an associate general counsel, hired to run the calendar. The cash band on that posting sits in the pay section below.

Life-sciences serial acquirers title it more tightly. A global pharmaceuticals group still publishes a Senior Antitrust Counsel requisition written to support a Head Legal Antitrust and to cover M&A and BD&L filings: assessing potential filings and timing, obtaining clearances, and running diligence, clean-team and integration planning. The same seat also owns day-to-day counseling. The gate is eight to ten years of EU competition work. That is an in-house filing manager with a behavioral book attached, not a free-standing “antitrust economist” title.

FMCG in Brussels can run the opposite brief. Unilever’s Global Competition Team is described on a CityDox posting as four senior lawyers and one paralegal or assistant, business-partnering global sales. The posting says a strong expertise in behavioral antitrust, as opposed to the filing calendar, which is of less importance to the role, is key. That is the one-deal side of the line written as a job description: own the sales-compliance program; rent the filing calendar. Salesforce’s public Code of Conduct names an Antitrust Legal team as the routing point for competitor conversations, while M&A legal is a separate buy-side contracts desk. Even a serial software acquirer splits “do the deal” from “clear the deal.”

Public bodies in the same three cities are buyers of the skill and the main credential factory for the in-house hire. A July 2026 Commission vacancy for Unit COMP.C.5 — mergers in IT, internet, consumer electronics, telecoms and media — describes that unit as currently composed of about 28 staff, including two case managers; case teams always comprise a case manager, at least two case handlers and a secretary. A companion notice for Unit COMP.D.4 writes economic and data analysis into the case-handler job and treats a background in law or economics as an asset. The CMA Legal Service embeds lawyers on merger projects; a 12 December 2023 blog recorded over 50 secondees from over 20 law firms since 2018, including placements in Mergers. Steptoe, citing OPM in June 2026, recorded that roughly one in five federal lawyers at end-2024 had left by March 2026, and that the FTC and DOJ were recruiting for merger shops as of that writing. Those alumni appear on shortlists. They are not, by themselves, filing managers.

The Brussels in-house credential is the IBJ-IJE company-lawyer title, not the Bar. The institute, in a page last updated on 23 April 2026, protects juriste d’entreprise / bedrijfsjurist, puts a Competition Law practice group among its groups, and describes a community of 2,500 legal professionals at an annual fee of €414. EU-list or B-list registration at the Brussels Bar is the gate for a firm seat. A chief legal officer hiring into the company is hiring an IBJ-IJE lawyer who can read a model and run a calendar, not a member of the Bar who will appear.

On the same 15 closed Brussels in-house files, counter-offer incidence was 27 percent and the median offer-to-acceptance window was 13 working days. They are not the reason the filing-manager seat stays open. The reason is the brief.

Of the 8 filing-manager seats we closed, 4 began as generic competition-counsel requisitions and only named Form CO, Form FS-CO and the briefing paper after the first intake. Those four still closed. They consumed the sixth and seventh months of the 4-to-7-month band. A page that reported only the 93 percent completion rate would hide that. The uncomfortable number is the one that made those files slow: we cannot write the company’s mind for it, and a search opened on a slogan will not produce a filing manager.

Two composites from that book, described by category only. A PE-backed healthcare platform asked for a Senior Antitrust Counsel to support a Head Legal Antitrust on M&A and BD&L filings. The brief named timing, clearances and clean-team work from the first call. The search closed in five months. The hire sits under the general counsel and owns the filing calendar; the panel still holds Phase I remedies. A listed industrial with one concentration in a decade opened a standing filing-manager requisition, interviewed agency alumni, and then kept the Brussels panel. We completed the process because the client insisted. The head of legal later converted the open role into a general competition seat. That is a completed file that did not vindicate the original brief.

Coverage has a known blind spot. Sartori maps nearly 1.5 million lawyer profiles globally, and the Brussels cut of that mapping still misses merger-filing work that an existing head of legal or competition counsel absorbs without a requisition, a posting or a mandate. When we tell a chief legal officer what the market for this seat looks like, we are describing the part that becomes visible. The quarterly survey since 2019 can see the companies that will talk about a rented calendar. It cannot see the ones that folded Form CO into last year’s job description and never called.

Economics literacy is a gate on the public side and a preference on the company side, not a separate job. DG COMP writes economic and data analysis into the case-handler notice and puts the Chief Economist’s team on Phase II (Chambers EU, 2026). Company ads ask for merger-review experience and timing judgment. The in-house hire is the lawyer who can read the model, commission the efficiencies pack the April 2026 draft guidelines want before notification, and still run the calendar. Competition economics as an academic discipline is a different query. Antitrust economics as a consultancy line is a panel instruction, not a payroll title.