Thompson Street Capital Partners

St. Louis-based middle-market private equity firm. Founded in 2000. Manages over $4.5 billion in assets as of September 30, 2025, and has acquired more than 250 companies since inception (TSCP on ATIS/Vinspec announcement, March 2026). Software & technology is one of three declared sector focuses alongside life sciences & healthcare and business & consumer services and products (TSCP website).

Mandate and check size

The current active fund is TSCP VI, closed at more than $1.5 billion in commitments. TSCP VI writes equity checks of $50 million to $250 million into companies with $5 million to $50 million of EBITDA (TSCP press release, Fund VI close). Fund V was $1.15 billion (PE Hub, Fund V coverage).

At typical software multiples (10–15x EBITDA, 3–7x ARR), that check range implies platform deals at $10M–$70M+ ARR. The top of that window sits inside the Rivas Will $50M ARR ceiling; the bottom is well inside the band. Strategy is control investments in founder-led middle-market businesses via recapitalisations, management buyouts, corporate divestitures, and take-privates (dfkcompany.com, TSCP overview).

TSCP has also run at least two single-asset secondary (continuation) transactions. The most recent, September 2024, was a continuation vehicle for Gurobi Optimization co-led by Hamilton Lane and StepStone Group (TSCP press release, continuation fund; Secondaries Investor, 18 September 2024). The GP-led pattern is worth flagging: TSCP will structure to hold the best software assets past Fund-level exit dates rather than force-sell them.

Recent cited exit: Data Dimensions to One Call (16 April 2026)

On 16 April 2026 TSCP announced the sale of Data Dimensions (Janesville WI, founded 1982; EDI clearinghouse and technology services for healthcare, insurance, and government end markets) to One Call, a Jacksonville FL–based technology-enabled care coordination and workflow intelligence platform for the workers' compensation market. Terms were not disclosed; the close completed 15 April 2026 per One Call's completion release and Data Dimensions' own announcement (TSCP primary release, 16 April 2026).

Entry-to-exit math: TSCP initially partnered with Data Dimensions in 2019 (Baird transaction page; PE Hub, 16 April 2026). Seven-year hold. During TSCP's ownership, Data Dimensions ran a platform-plus-tuck-in programme — PE Hub cites the acquisitions of WorkCompEDI and Providerflow under TSCP — confirming that the ATIS buy-and-build pattern is not isolated to the vertical-transportation portfolio; TSCP structures the same way across sectors when the platform supports it. Bryan Doyle transitions from President and CEO of Data Dimensions to Chief Business Officer at One Call post-transaction, another data point for how TSCP structures management continuity into its exits.

J.C. Wetzel is named as Managing Director on the deal in the primary TSCP release — a previously-unnamed (in this brief) TSCP MD surfacing as the software-side deal lead. Baird and Bailey & Company served as financial advisors; Polsinelli served as legal advisor. Per Baird's dealcard, Baird ran the sell-side; two banks on a mid-market exit signal a competitive process, not a bilateral carve-out.

This is the first cited TSCP software-portfolio exit of 2026 and resolves what had previously been an open thread on the firm's 2026 exit cadence. Combined with the March 2026 Karpel Solutions platform investment and the ATIS tuck-in programme (Bayline Dec 2025, Soberman Mar 2026, Vinspec Mar 2026), TSCP is demonstrably active on both sides of the Fund VI portfolio in 2026 — buying new platforms into software, tucking into existing ones, and exiting mature holdings to strategics. Founders in workflow-intensive, regulated, transaction-based software sub-verticals (EDI, clearinghouse, claims automation, compliance) should note that TSCP has a cited 7-year hold pattern with a working strategic-buyer exit path — not a "force a financial sponsor-to-sponsor sale at year five" pattern.

Why this buyer matters to the Rivas Will band

Two things.

One — the platform deals sit on the Rivas Will ceiling, not inside the band. A $10–25M ARR founder talking to TSCP directly is being bought as a platform, usually on the strength of a dominant niche position. Examples from the current portfolio:

• Karpel Solutions (St. Louis MO) — announced 24 March 2026. "Prosecutor by Karpel" is described as the most widely used prosecutor case-management software in the United States; the company has been operating for more than 30 years and is sold to state and local government agencies (Preqin asset profile; Pulse2 coverage; Scherzer Deal Report, week of 23–27 March 2026). This is a government-tech / legal-tech vertical SaaS with a dominant-niche profile — the exact shape TSCP buys.
• Silverchair (Charlottesville VA) — scholarly publishing infrastructure. In October 2024, Silverchair announced an agreement to acquire ScholarOne from Clarivate (NYSE: CLVT), closing in Q4 2024 (Clarivate press release, 28 October 2024; The Scholarly Kitchen, 28 October 2024). This is a classic "buy critical workflow software off a public owner that doesn't want it" move. Silverchair + ScholarOne together is a vertical SaaS platform for scholarly publishers.
• Gurobi Optimization (Beaverton OR) — mathematical optimisation software. Held via continuation fund since September 2024.
• MediaRadar — advertising intelligence SaaS. Matt Krepsik was installed as CEO in 2025; Dan Cooper is the named TSCP director on the deal. Co-invested with Endicott Capital (MediaRadar CEO announcement).

Two — the tuck-in programme is where Rivas Will prospects actually land. TSCP's ATIS platform (elevator and escalator safety inspection software and managed services, acquired September 2024) is running a visible add-on cadence in the Rivas Will size band:

• M.A.N. Elevator Inspections (Florida), 20 November 2025 (TSCP primary release; Elevator World, 21 November 2025)
• Bayline Lift Technologies (Mid-Atlantic), December 2025 (Morningstar / BusinessWire)
• Soberman Engineering (independent vertical-transportation consulting), 10 March 2026 (PE Hub)
• Vinspec (Alberta, Canada), 31 March 2026 (BusinessWire; globenewswire dateline 31 March 2026 09:00 ET)
• Vermont Elevator Inspection Services (asset purchase, The Middle Market)

Five disclosed ATIS tuck-ins inside five months (M.A.N. Nov 2025, Bayline Dec 2025, Soberman Mar 2026, Vinspec Mar 2026, plus Vermont) is a roll-up cadence, not an opportunistic one. Vertical-transportation inspection software was not a sub-vertical on the Rivas Will radar before this brief; it is now.

Structural note on the operating banner. "ATIS" in this brief is shorthand for ATIS Ascenda Partners, LLC — the merged entity formed on 25 January 2023 when ATIS (St. Louis), Liberty Elevator Experts, and KJA Consultants combined into a single TSCP-backed platform (globenewswire press release, 25 January 2023; St. Louis Business Journal, 12 September 2023). Soberman and Vinspec were acquired by KJA inside ATIS Ascenda, not by ATIS-the-original-entity. The Bayline and M.A.N. deals went into the U.S. ATIS arm. This three-banner structure (KJA = Canada, ATIS = U.S., Liberty = pre-merger U.S. predecessor folded in) explains why the operating-group press feeds need to be queried separately when refreshing the deal cadence — Vinspec's primary dateline lives on the KJA newsroom, M.A.N.'s on TSCP's own news archive.

Key people

• Bob Dunn — Managing Partner, head of acquisitions. Quoted on the Fund V close: "This investment pace is right on for five years" (PE Hub, Fund V). LinkedIn: bob-dunn-61ba463.
• Jim Cooper — Managing Partner. Named alongside Bob Dunn in PE Hub's Fund V coverage.
• Ray Wagner — Managing Director. Sweet-spot check size quoted at $25M per Signal/NFX (Signal/NFX TSCP firm page).
• J.C. Wetzel — Managing Director. Deal lead on the April 2026 Data Dimensions exit to One Call: "Data Dimensions has built a differentiated platform at the intersection of healthcare, insurance and technology" (TSCP press release, 16 April 2026).
• Dan Cooper — Director. Named on the MediaRadar CEO transition.
• Clayton Milburn — Director (TheOrg leadership team).

What I know about how they behave

• They are not a software-only shop. TSCP also owns industrial services, food & beverage (Freddy's Frozen Custard, sold to Rhône in September 2025), and healthcare services. Founders selling into TSCP talk to a generalist mid-market fund, not a software specialist. That affects the diligence style and the likely portfolio-company references.
• They like founder-led, not VC-backed. The marketing language on their website and in every press release emphasises "founder-led middle-market businesses." Bootstrapped vertical SaaS founders fit the pitch; heavily-venture-funded ones do not.
• They build platforms and tuck in — across sectors, not just vertical-transportation. The ATIS pattern (Bayline Dec 2025, Soberman Mar 2026, Vinspec Mar 2026) is the most visible roll-up on the current portfolio, but the Data Dimensions exit surfaces the same model inside healthcare/insurance/government EDI infrastructure: under TSCP, Data Dimensions acquired WorkCompEDI and Providerflow before being sold to One Call (PE Hub, 16 April 2026). A founder with $3–8M ARR in a regulated inspection, compliance, clearinghouse, or government-software niche is a tuck-in candidate, not a platform candidate.
• Seven-year holds with a working strategic-exit path. Data Dimensions (2019 → April 2026, sold to One Call) is the first cited 2026 TSCP software exit and a concrete datapoint on hold length. Founders selling control to TSCP should model a 6–8 year working relationship, not a 3–5 year financial-sponsor flip. Management continuity into the exit is the norm — Bryan Doyle transitioned from Data Dimensions CEO to Chief Business Officer at One Call on close.
• They structure for long holds. Two continuation funds in the past few years means TSCP will move the best assets into secondary vehicles rather than force a sale at the Fund's end-of-life date. Founders selling a minority position into TSCP should expect the firm to still be a shareholder five or seven years out.

2026-04-30 cycle-back

Nine-day cycle-back since the 21 April refresh. Six paid SERP queries via rivas-research ask (BD ledger 72 → 78). Findings:

• No new platform, exit, or leadership announcement in the 4/16 → 4/30 window. The 16 April Data Dimensions exit to One Call remains the latest announced TSCP-side event. The TSCP news archive (news index, retrieved 2026-04-30) carries the 4/16/26 Data Dimensions release as its top entry and the 3/31/26 Vinspec release as the second. No new release between the two checkpoints.
• One missed historical tuck-in surfaced: M.A.N. Elevator Inspections (Florida), 20 November 2025. That deal was live on the TSCP news feed and on Elevator World for ~5 months before the 21 April refresh captured the more recent ATIS items but not this one. The 4/21 ATIS list ran four entries (Bayline Dec 2025, Soberman Mar 2026, Vinspec Mar 2026, Vermont Elevator); M.A.N. is the fifth. Fifth ATIS tuck-in in the past five months — the roll-up cadence is denser than the prior brief framing implied.
• Structural correction: the operating banner is ATIS Ascenda Partners, LLC. The brief had been treating "ATIS" as a single-entity tuck-in roll-up. In reality, the operating banner since 25 January 2023 is ATIS Ascenda Partners, LLC — a tri-merger of ATIS, Liberty Elevator Experts, and KJA Consultants (globenewswire, 25 January 2023). KJA is the Canada arm; ATIS-the-original is the U.S. arm. The Vinspec deal is correctly read as KJA-acquires-Vinspec inside ATIS Ascenda, not as ATIS-acquires-Vinspec.
• Rule fired and vindicated. The "<buyer> 2026 leadership OR exit OR acquisition OR merger" SERP scan promoted from today's earlier REFLECT (after three same-day occurrences on tribute-technology, thoma-bravo, and constellation-software) surfaced both the 5-month M.A.N. coverage gap and the 39-month ATIS Ascenda banner correction on first application against TSCP. The rule is paying for itself on the very next refresh.

Open threads

• Is there an active TSCP Fund VII, or is Fund VI still in deployment? Every 2026 press release — including the April 16 Data Dimensions exit — refers back to the Fund VI framing; no public Fund VII announcement has surfaced in free sources yet. The April 2026 Data Dimensions exit is a realised-proceeds event that normally precedes a Fund VII raise by 6–18 months; worth re-checking on the next TSCP refresh.
• What is Karpel Solutions' ARR? Prosecutor case management in 30+ states over 30+ years suggests something in the $20–50M range, but no disclosed figure exists. Worth a targeted lookup if Karpel becomes relevant to a prospect in government-tech.
• Silverchair + ScholarOne combined is now a scholarly-publishing infrastructure platform. That is a discrete sub-vertical (academic journal workflow, manuscript submission, peer-review management) Rivas Will has not mapped. Deserves its own entry in workspace/sector.md if a second prospect surfaces.
• ATIS is running one roll-up, but the Data Dimensions programme (WorkCompEDI + Providerflow tuck-ins under TSCP) confirms the same buy-and-build model plays inside other niche inspection / compliance / clearinghouse software sub-verticals. Worth watching for a second TSCP platform built on the same template post–Data Dimensions exit.