Auto ancillary industry

4.3.1 The model and the master equation

An ancillary is an auto-components supplier. It sells parts to OEMs as original equipment, to the replacement market, which is the aftermarket, and abroad as exports. It takes its volumes from someone else's demand cycle and hands concentrated customers an annual price-down. And yet the best ancillaries out-earn and out-compound their OEMs. The master equation explains how:

Ancillary revenue = industry vehicle volumes × content per vehicle × market share (± aftermarket & exports)

Why does content per vehicle drive growth?

Industry volumes might compound at 4 to 6%. Content per vehicle is the structural multiplier, and it can run at 8 to 12% for years. Regulation drives it. BS-VI emission hardware added roughly ₹8,000 to 15,000 to a 2W and ₹50,000 to 2,00,000+ to CVs (illustrative). Airbag and safety mandates add more, and so do sensors. Premiumization adds more again: LEDs replacing bulbs, alloy wheels, infotainment. A modern car's electronics share of BOM has climbed for two decades. Then there's electrification. An EV's wiring harness, power electronics, and thermal management carry 2 to 3× the kit value of their ICE equivalents for suppliers positioned there. So a supplier compounding content 8% and gaining a point of share grows ~13 to 14% in a 4%-volume year: 1.04 × 1.08 × 1.02 − 1 ≈ 14.6%. The factors multiply. They don't add, and the same rule held when you split price from volume in the consumer playbook.

Kit value is the India-market term for content per vehicle summed across a supplier's product lines. An Uno Minda-style disclosure (illustrative) reads: "our kit value on a premium motorcycle is ₹5,200 vs ₹2,100 on an economy model." Growing kit value means winning more parts per vehicle platform, and it's the cleanest structural growth story in the sector. Audit it by asking which specific products were added per platform, and what EV kit value runs at against ICE.

4.3.2 The three-market mix: OEM / aftermarket / exports

A 40/35/25 OEM/aftermarket/export mix works as a shock absorber. The 2019 Indian CV crash hurt pure-OEM suppliers ~2× harder than balanced ones. But exports import someone else's cycle. With Bharat Forge-style US Class 8 exposure (illustrative), Ohio freight data moves a Pune forging line.

Every mix comes with a cycle, so your job is to work out which cycles you own and how many.

Why is client concentration a risk?

Client concentration is the quiet killer. One OEM at 40%+ of revenue leaves your capex, pricing, and receivables all hostage to one purchasing department. The gold standard is an explicit diversification rule, and Motherson's famous "3CX10" rule is the template. No single component, customer, or country may exceed 10% of revenue. It's a real, stated policy, though you should verify the current formulation in the annual report. When you see a 3CX10-style rule plus kit-value growth, you're looking at the ancillary version of a compounder. One client at 50% and one product at 70% is something else entirely: a call option on someone else's model cycle.

4.3.3 RM pass-through and the margin lag (worked)

Metals (steel, aluminium, copper) plus polymers make up 55 to 70% of an ancillary's revenue. Large OEM contracts are indexed. Selling prices reset periodically to a lagged average of the metal index. That's usually every quarter, sometimes every half-year. The pass-through protects the rupee spread per unit, but with a lag, and it never protects the margin percentage. The result is a mechanical, forecastable margin wave that quarterly-EPS tourists misread every single cycle. Here's how it plays out:

Worked example: how a copper price rise moves gross margin

"Meridian Harness" (synthetic). In the baseline quarter revenue is ₹100 cr and RM is ₹60 cr. Copper accounts for ₹24 cr of that and other RM for ₹36 cr, so gross margin is 40%. The contract resets price each quarter to the prior quarter's average copper price. The copper index starts at 100, jumps to 120 in Q1, holds at 120 in Q2 and eases to 110 in Q3.

You can read three lessons straight off the table.

1. Q1 is the squeeze quarter. Costs reset instantly while prices lag, and 4.8 points of gross margin vanish even though nothing is wrong with the business.
2. Q2 is the recovery quarter. The rupee spread is fully restored, with gross profit back at ₹40.0 cr, yet the percentage is still 38.2% against 40%. The pass-through has inflated the denominator. So the spread is preserved while the optics are diluted, and a company can truthfully say "full pass-through achieved" while screens show margin down 180bps.
3. Q3 is the flattered quarter. When the metal falls the lag works in reverse. You're buying cheap copper while selling at last quarter's high price, and margin prints above baseline. Managements rarely flag this one.

Never annualize a squeeze quarter or a flattered quarter. Model the lag explicitly and judge the business on spread per unit. The aftermarket channel helps here too. Prices there are sticky upward, so it keeps some of every RM decline, one more reason the mix matters.

4.3.4 ROCE discipline: the test that separates suppliers from compounders

Ancillaries are capex-heavy businesses, spending 6 to 8% of sales in expansion phases, and they sell to customers who set the price. The mediocre ones earn 8 to 12% ROCE, at or below the ~12% hurdle, so their growth creates nothing. The compounders earn 18 to 25%+ in four ways. They add capacity only against won platforms, never against hopes. They keep working capital tight: OEM receivables are safe but take 45 to 60 days, and aftermarket inventory is the trap. They tilt the mix toward value-added work, because design-led parts out-earn build-to-print. And they grow kit value on existing assets, which is the highest-ROCE growth there is, more content through the same plant.

Run the ROCE bridge on any ancillary: ROCE = EBIT margin × capital turns. A supplier with a 12% EBIT margin and 2.5× turns earns a 30% pre-tax ROCE. That's a better business than a 16%-margin, 1.2×-turns one at 19%. It's far better than the 9%-margin, 1.3×-turns build-to-print shop at 12%, which is hurdle wallpaper. So when an ancillary announces a big greenfield "for future EV orders," only one question matters.

Is there a contracted platform behind the concrete?

4.3.5 ICE-only vs EV-agnostic vs EV-upside: the portfolio X-ray

Sort every product line in the supplier's portfolio into three buckets. It's the brief's "ICE-only vs EV-agnostic" test. Through the 2020s and into the 30s it's the first thing a buyer of ancillary equity should do:

How does EV exposure change an ancillary's value?

Then weight the buckets by revenue. A supplier with 70% ICE-at-risk revenue and no EV order wins is a melting ice cube, whatever its current P/E. Value it like a run-off: finite-life cash flows, no terminal value on the at-risk pool. Motherson/Uno Minda-style portfolios (harnesses, lighting, switches, mirrors, all agnostic-to-upside) sail through the same transition that beaches a pure engine-parts machinist. Globally, the same X-ray sets Aptiv-style electrical architecture (agnostic/upside) against pure exhaust/emissions names (at-risk). BorgWarner's public pivot is the transition managed as capital allocation. It bought EV drivetrain businesses while spinning off ICE-heavy units (illustrative, so read its "Charging Forward" strategy disclosures as a case).

Don't overcorrect, though. ICE-at-risk pools will take 15 to 25 years to drain in India. 2W and CV electrify slower than PV, and the aftermarket for the existing fleet persists for decades. The bucket tells you the direction of terminal value. The local EV-adoption curve tells you the speed. You need both.

4.3.6 Ancillary KPI panel and red flags

Here are the brief's red flags, operationalized:

• An ICE-only portfolio with zero announced EV-platform wins while EV mix in its segment climbs.
• Client concentration above 35 to 40%, where one purchasing decision decides your thesis.
• Capex on spec with ROCE already below the hurdle.
• RM "squeeze" excuses when the spread per unit is shrinking along with the percentage. That's pricing-power loss dressed up as commodity noise.
• Receivables stretching beyond contract terms. Your OEM is either stuffing its channel or bleeding, and either way you're the bank now.