The Thailand Cohort Map

Thailand's SET Mainboard universe is 641 firms — and 77.5% of them are small-cap.

That single number sets the analytical posture for everything that follows. A market dominated by sub-USD 300 million issuers behaves structurally differently from one anchored by mega-cap incumbents. SET Mainboard is not Korea's KOSPI; it is closer to a long-tail distribution where 486 small-cap firms compete with 28 large-caps for the same governance scrutiny resources.

This is the cohort map for the Thailand Foundation Series. Every subsequent piece — NVDR mechanics, family conglomerate clusters, audit concentration, the vs-Korea comparison — references the distributions established here.

The universe

Apex G-Score Thailand scores 641 listed issuers on the Stock Exchange of Thailand Mainboard. The 229 firms listed on the Market for Alternative Investment (MAI) are excluded by design: MAI's small-cap free-float minimum and lighter SET-listing-rule envelope put it in a different disclosure-tier and liquidity-tier from the SET Mainboard, so the framework treats it as a separate scoring problem. REITs, property funds, infrastructure funds, debt-only securities, and ETFs are also excluded — these are not corporate governance entities in the operational sense the framework measures.

The result is a clean SET Mainboard canvas of 641 issuers, scored under Apex G-Score's TBR v2.0 weights: Transparency 0.30, Balance of Power 0.30, Conflict-of-Interest Risk 0.40.^[1]

Archetype distribution

The framework classifies each firm into one of five archetypes, with a Kill Switch override layer for governance-collapse cases that defy archetype reading:

Archetype	n	%
Celestial	112	17.5%
Hidden Gem	221	34.5%
Chameleon	248	38.7%
Poison Apple	20	3.1%
Time Bomb	0	0.0%
KS override	40	6.2%

Two numbers anchor the Thailand reading.

Hidden Gem at 34.5% is the largest non-Chameleon share in the eight-market series.^[2] No other Asian market in the framework's coverage produces this many firms that fall short on transparency yet still demonstrate functional balance-of-power and acceptable conflict-of-interest profiles. The Thai pattern is recognizable: small-cap industrial and property issuers with limited bilingual disclosure but with auditor independence intact and related-party perimeters disciplined enough to avoid R-axis alarm. Two hundred of those 221 Hidden Gems — 90.5% — are small-cap. Hidden Gem is, structurally, a small-cap phenomenon.

Chameleon at 38.7% is the dominant archetype — but the sub-tag breakdown matters more than the headline. Of those 248 Chameleon firms, 158 (63.7%) are B-weak. Seventy-nine are R-weak. Nine are balanced across all three axes. Two are T-weak. The Thai Chameleon problem is not three-axis mixed-signal noise. It is a Balance-of-Power axis problem with two other axes performing.

The Time Bomb category sits at zero. Firms that would meet the all-three-axes-failing definition are absorbed into the Kill Switch override layer before they surface as scored firms in the lowest archetype tier — captured by hard-trigger indicators (audit failure, non-filing, trading suspension cascade) that route distress firms out of the archetype taxonomy entirely.

Axis statistics

Axis	Mean	Median	sd
Transparency (T)	68.33	72.0	7.53
Balance of Power (B)	72.79	74.0	13.40
Conflict-of-Interest Risk (R)	73.35	75.0	9.33

Three axes clustered between 68 and 73 is a balanced-three-axis signature. It does not match Korea's R-primary profile, where R-axis means run twelve to fifteen points above B-axis means. It does not match Japan's keiretsu-shaped distribution. Thailand's mean signature is its own pattern.

What the means do not show: the B-axis carries the highest standard deviation of the three at 13.40, nearly double the T-axis dispersion. B-axis dispersion is where Thai governance separates. The mean is healthy; the tails are not. The 158 B-weak Chameleons live in the lower B-axis tail, and the institutional mechanism that produces that tail is the subject of Note 2.

The current axis statistics reflect a material recalibration applied to the Thai universe in early 2026.^[3] Before correction, T-axis mean sat at 79.86 (median 85.0) — a saturation pattern indicating the indicator stack was admitting too many firms to top-decile transparency scores. The correction tightened filing-timeliness, audit-opinion, and non-Big-4 detection rules; T-mean dropped to 68.33, and Celestial share fell substantially as a result. B-axis mean shifted more modestly, from 75.30 to 72.79. The post-correction reading above is the production calibration.

Cap band and industry

The cap-band distribution is steeply tilted small.

Band	Threshold	n	%
Large	≥ THB 100B	28	4.5%
Mid	THB 10B–100B	113	18.0%
Small	< THB 10B	486	77.5%

Cap × archetype cross-tabulation reveals that SET Mainboard's structural composition varies sharply by size. Among the 28 large-cap firms, 57.1% are Chameleon and only 10.7% are Hidden Gem — large-caps clear the T-axis bar but split between perfect-three-axes profiles and structurally-mixed-signal at the B and R level. Mid-cap distribution is similar: 54.9% Chameleon, 22.1% Celestial. Small-cap, by contrast, is where Hidden Gem dominates (41.2% of small-cap firms), and where 24 of the 40 Kill Switch firms sit (60% of all KS).

A separate cohort of 14 firms has degraded market-cap data — and 13 of those 14 are Kill Switch flagged, almost all suspended-trading cases where data feeds break down precisely because the firm has stopped reporting. Data quality and KS designation correlate near-perfectly at the tail.

By industry, the universe spreads across eight SET groups:

Industry	n	%
Services	135	21.1%
Property & Construction	114	17.8%
Industrials	101	15.8%
Agro & Food	71	11.1%
Financials	71	11.1%
Resources	57	8.9%
Consumer Products	47	7.3%
Technology	45	7.0%

Services, Property & Construction, and Industrials together hold 55% of the Mainboard. The industry tilt carries archetype implications.

Property & Construction posts the highest Hidden Gem density at 42.1% — small to mid-cap developers with limited bilingual disclosure but with controlling-shareholder structures stable enough to avoid R-axis flags.^[5] Industrials carries the highest Poison Apple share at 6.9%, more than double the universe baseline — the cohort of transparent-facade firms with structural B or R weakness clusters in this segment, often in cross-directorship-dense subsectors and reverse-takeover pathway issuers. Agro & Food is bimodal: 28.2% Celestial (the highest in the universe) and 52.1% Chameleon simultaneously — the family-cluster anchored cohort where Sahapat, Boonrawd, Mitr Phol, and Thai Union sit. Technology has the lowest Kill Switch rate at 2.2%, reflecting the cohort's recent IPO vintage and shorter audit-and-filing histories.

Index membership

Index inclusion within the scored universe distributes as follows:

• SET50: 49 firms
• SET100: 99 firms
• SETESG: 121 firms
• SETHD (high-dividend): 30 firms
• SETWB (well-being): 29 firms
• SETCLMV (regional): 57 firms

The SET50 archetype distribution, compared to the full universe, sharpens the large-cap reading.

Archetype	SET50 (n=49)	Universe (n=641)	Δ
Celestial	24.5%	17.5%	+7.0pp
Hidden Gem	12.2%	34.5%	−22.3pp
Chameleon	59.2%	38.7%	+20.5pp
Poison Apple	4.1%	3.1%	+1.0pp
KS	0.0%	6.2%	−6.2pp

SET50 is a Chameleon-and-Celestial cohort. Hidden Gem is essentially absent from the index (only 6 firms, against 22.3 percentage points underweight) because Hidden Gem firms by definition have T < 70, and SET50 firms tend to clear the 70 mark on transparency. Zero Kill Switch firms in SET50 confirms a structural-quality floor: the index's liquidity and disclosure thresholds filter out the distress cohort entirely. The +20pp Chameleon overweight is the editorial fact: SET50, despite being the index of large-cap quality, is structurally tilted toward mixed-signal firms with one axis underperforming.

SETESG — the operative successor to the retired Thailand Sustainability Investment (THSI) brand^[4] — at 121 firms is the most analytically interesting voluntary index. The selection-bias question of whether SETESG firms are disproportionately Celestial or whether the index admits Chameleon and Hidden Gem firms in significant numbers is the subject of a later Note in this series.

Kill Switch profile

Forty firms (6.2% of the universe) carry a Kill Switch override. Trigger distribution:

Trigger family	n firms
Non-filing	17
Trading suspension cascade	16
Audit-opinion failure (disclaimer/adverse)	10
SEC criminal complaint	8
NVDR extreme dilution	1
Backdoor listing + sustained loss	1

Eleven firms carry two or more triggers simultaneously. The most common combination — audit-disclaimer paired with non-filing — affects five firms.

Non-filing is the modal Thai distress signature. Disclosure simply stops. The SET filing system records the absence; the framework records the absence; the firm enters the cascade that ends in trading suspension. The pattern is not unique to Thailand, but the relative weight — 17 of 40 KS firms, 42.5% — is. The single NVDR-extreme-dilution case and the single backdoor-listing-plus-loss case sit in the tail of the trigger distribution as Thailand-distinctive override pathways that no other market in the eight-market series carries.

Structural-quality floor: auditor concentration

A baseline cohort statistic worth recording before the series proceeds: Big-4 auditors cover 69.9% of the SET Mainboard universe — EY 32.0%, KPMG 17.8%, PwC 13.9%, Deloitte 4.5%, with another 1.7% in other Big-4 affiliations. The remaining 30.1% — 193 firms — uses non-Big-4 auditors. The Big-4 / non-Big-4 split is not itself a governance verdict, but it is a structural-quality floor that the framework's transparency and audit-failure indicators read against. Most Kill Switch firms sit in the non-Big-4 cohort. The audit concentration deep dive is a later piece in this series.

A further cohort note: 20 firms in the universe (3.1%) are foreign-parent-controlled — DELTA, BBGI, BCPG, BGRIM and others — Thai-incorporated SET-listed entities with foreign multinational controlling stakes. All 641 firms are Thai-incorporated; the foreign-parent cohort matters for how the framework reads cross-border ownership versus Sino-Thai family ownership, which is the larger structural feature of the Thai Mainboard.

Where Thailand sits in the eight-market grid

Thailand's archetype distribution does not look like Korea's. It does not look like Japan's. It does not look like Hong Kong's or India's.

Korea's universe runs 88% Chameleon — a single dominant cohort defined by a single dominant axis weakness, the formal-independence collapse of the B-axis.^[6] Thailand's Chameleon share is less than half that figure, and the Hidden Gem buffer absorbs a third of the universe into a category Korea barely populates. Where Korea's reading is one-axis pathology applied uniformly across the market, Thailand's reading is a balanced three-axis distribution with structurally distinct tails.

The B-axis tail is the analytical entry point for the rest of this series. The mean B-axis number is 72.79 — apparently healthy. The 158 B-weak Chameleons say otherwise. The mechanism that produces both numbers at once is institutional, Thailand-distinctive, and absent from every other market the framework covers.

Note 2 documents that mechanism.

Archetype distribution, Apex G-Score Thailand v2.0. Chameleon dominant at 38.7%, Hidden Gem second at 34.5% — the largest non-Chameleon share in the eight-market series.

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The Apex G-Score framework currently covers 641 SET Mainboard listed companies as of the April 2026 production snapshot. Underlying data: FY2025 cross-section. Scoring under TBR v2.0 weights: Transparency 0.30, Balance of Power 0.30, Conflict-of-Interest Risk 0.40.