PER, EPS, PBR and BPS are calculated in-house from the last 4 quarters (2025Q3–2026Q2) · Dividend yield is based on ₩0 per share · Prices as of the 2026-10-02 close
Clean & Science, long the dominant player in Korea's home air-purifier filter market, returned to profit in the first half of 2026 after a 2025 factory-accident-driven slump, while simultaneously entering new markets such as AI data center and semiconductor cleanroom filtration.
Operating profit and net profit both turned positive in 2026Q1 and Q2, recovering from the 2025H2 factory-accident shock
Holds roughly 70% share of Korea's home air-purifier filter market, supplying finished filters to Samsung Electronics, LG Electronics and Coway
Secured its first reference supply of AI data center HVAC filters, diversifying into semiconductor cleanroom, MLCC and PFAS-compliant filtration
The 2025 debt ratio of 343.8% is the highest in the past four fiscal years, indicating persistent financial strain
Cumulative owners' net income over the trailing four quarters (2025Q3-2026Q2) remains in the red
Founded in 1973, Clean & Science is an environmentally focused filtration specialist that has long produced automotive and industrial filter media along with finished filter products.
Revenue is concentrated in finished filters at roughly 60% of sales, followed by automotive paper media at about 26%, melt-blown (MB) nonwoven media at about 7%, merchandise sales at about 5%, and industrial paper media at about 2%.
Its core product, home air-purifier filters, commands roughly 70% of the domestic market, supplying finished filters to major appliance makers including Samsung Electronics, LG Electronics and Coway.
The company has built a vertically integrated structure spanning raw filter media to finished products, enabling rapid response to customer specifications. In automotive filter paper, it established proprietary technology through a seven-year technical partnership with Germany's J.C.
Binzer, while its MB nonwoven capability stems from a technology tie-up with America's AAF beginning in 2000. In 2020 the company added a healthcare and surgical mask business to diversify its product lineup.
Overseas, it operates subsidiaries in the United States and China and established a Thai production subsidiary in 2022 to improve filter-segment cost structure and diversify exports.
Filter media manufacturing is a capital-intensive, equipment-heavy industry with high entry barriers, resulting in an oligopolistic market structure, and the company is estimated to hold roughly 35% share of the overall domestic filter market.
| Quarter | Revenue | Operating profit | Op. margin |
|---|---|---|---|
| 2025Q2 | ₩24.8B | ₩1.1B | 4.6% |
| 2025Q3 | ₩17.3B | -₩1.8B | −10.5% |
| 2025Q4 | ₩17.7B | -₩1.4B | −8.0% |
| 2026Q1 | ₩24.9B | ₩800M | 3.4% |
| 2026Q2 | ₩25B | ₩400M | 1.6% |
| Year | Revenue | Operating profit | Net income (parent) | Op. margin | ROE | Debt-to-equity |
|---|---|---|---|---|---|---|
| 2022 | ₩86B | -₩10.9B | -₩15.1B | −12.7% | −55.6% | 247.8% |
| 2023 | ₩92.5B | ₩900M | ₩900M | 1.0% | 3.2% | 238.3% |
| 2024 | ₩84.6B | -₩800M | -₩7.4B | −1.0% | −37.7% | 319.5% |
| 2025 | ₩86.1B | -₩1B | -₩3.4B | −1.1% | −20.0% | 343.8% |
Consolidated basis (financial statements including subsidiaries) · Final figures from DART filings · Net income attributable to owners of the parent · Data as of 2026-08-23
Consolidated revenue in 2025 came to KRW 86.098 billion, a modest increase from KRW 84.623 billion in 2024, but operating profit registered at negative KRW 0.965 billion, marking a second straight year of operating losses following negative KRW 0.849 billion in 2024.
Owners' net income was negative KRW 3.371 billion in 2025, a smaller loss than the negative KRW 7.407 billion posted in 2024, yet the company remained in net-loss territory.
By contrast, 2023 revenue of KRW 92.497 billion produced operating profit of KRW 0.938 billion and owners' net income of KRW 0.903 billion, marking a turn to profitability from the large 2022 loss (operating loss of KRW 10.900 billion, net loss of KRW 15.099 billion), underscoring significant volatility over the past four years.
On a quarterly basis, 2025Q2 revenue of KRW 24.756 billion with operating profit of KRW 1.140 billion looked solid, but both revenue and profitability deteriorated sharply in Q3 (revenue KRW 17.317 billion, operating loss KRW 1.818 billion) and Q4 (revenue KRW 17.681 billion, operating loss KRW 1.419 billion).
This is attributed to a factory accident in the second half of 2025, with the owners' net loss widening to KRW 2.517 billion in Q4.
Revenue then recovered to KRW 24.873 billion in 2026Q1, returning to profit with operating income of KRW 0.839 billion and owners' net income of KRW 1.383 billion, and the profitable trend continued into Q2 with revenue of KRW 24.969 billion, operating profit of KRW 0.389 billion and owners' net income of KRW 0.141 billion.
Still, cumulative owners' net income over the trailing four quarters from 2025Q3 through 2026Q2 stood at negative KRW 2.014 billion, indicating the recovery is underway but has not yet reached full normalization.
On the balance sheet, the debt ratio climbed steadily from 238.3% in 2023 to 319.5% in 2024 and 343.8% in 2025, reflecting a growing financial burden over the past three years.
In Korea's home air-purifier filter market, Clean & Science's filter segment maintains a stable revenue base with roughly 70% market share, though profitability remains constrained by rising cost burdens.
As air purifiers have become an essential appliance with sales expanding into B2B and B2G channels, the filter market as a whole is expected to grow in tandem.
While the traditional growth engines of home-appliance and automotive filters have reportedly entered a demand slowdown, the company maintains cost competitiveness through a vertically integrated system producing everything from MB raw media to finished filters.
A new demand driver has emerged from the expansion of AI data centers, which is boosting demand for high-performance HVAC filters, and the company is also extending into cleanroom filters for semiconductor and multilayer ceramic capacitor (MLCC) production processes.
Semiconductor cleanrooms require HEPA, ULPA and chemical filters while MLCC production needs water-treatment filters, as semiconductor manufacturing demands high cleanliness levels since particulate contamination directly affects product yield.
Tightening regulation of per- and polyfluoroalkyl substances (PFAS) is also cited as a new business opportunity, and the company already supplies PFAS-blocking HVAC filters to a US motion-and-control company.
Filter media manufacturing itself is a capital-intensive, equipment-heavy industry that creates high entry barriers for new competitors, resulting in an oligopolistic structure that tends to preserve the relative standing of incumbent producers.
According to a July 30, 2026 report from research firm Buffett Lab, the company secured its first reference supply of AI data center HVAC filters, delivering pre-filters and medium filters to a domestic AI data center operated by a global firm in early 2026.
The supply scale and customer name were not disclosed, but because data center filters are consumables requiring periodic replacement, whether this leads to recurring revenue as facility expansion and utilization increase is being watched as a key factor.
The same report noted the company has developed HEPA, ULPA and chemical filters for semiconductor cleanrooms and water-treatment filters for MLCC production, suggesting that expanding AI-related semiconductor facility investment could translate into related filter demand.
It also noted the company already supplies PFAS-blocking HVAC filters to a US motion-and-control company and plans to develop an improved-performance product within the year.
The report cautioned, however, that it will take time for these new businesses to translate into earnings improvement, and assessed that whether AI data center, semiconductor cleanroom, MLCC and PFAS-related filter revenue materializes at scale will be key to earnings recovery.
Meanwhile, the legacy air-purifier and automotive filter business returned to profit in both 2026Q1 and Q2, signaling a move away from the shock of the 2025H2 factory accident.
How long the company can sustain cost-improvement efforts through its Thai production subsidiary and its strategy of expanding sales to large OEM customers will also be a variable for future results.
The current share price appears to trade at a discount to net asset value, with the price-to-book ratio positioned below 1x. That said, the debt ratio has risen steadily over the past three years, warranting attention to the qualitative composition of the equity base.
On the earnings side, the multi-year pattern - swinging from a large loss in 2022 to a turn to profit in 2023, back to losses in 2024-2025, and now showing signs of profit recovery in the first half of 2026 - stands as a key variable for valuation judgment.
The fact that trailing four-quarter results remain in net-loss territory is also a reason to confirm whether the earnings recovery proves durable. The company has not paid dividends in recent years, which stands in contrast to peers in the sector that do distribute dividends.
As a small-cap stock, price volatility tied to trading volume and supply-demand flows also tends to run relatively high, which is worth factoring in.
PER, EPS, PBR and BPS are all calculated in-house (the same method as Naver and Toss) · Dividend yield = cash dividend per share from DART filings (supplemented by KRX) ÷ current price · As of 2026-08-23
Operating profit and owners' net income both turned positive for two consecutive quarters in 2026Q1 and Q2, confirming a shift away from the 2025H2 factory-accident disruption. Revenue also recovered clearly from KRW 17.3-17.7 billion in 2025Q3-Q4 to KRW 24.8-24.9 billion in 2026Q1-Q2. If this trend continues, it could serve as a gauge for the pace of earnings normalization.
The company secured its first reference supply of AI data center HVAC filters and is expanding into semiconductor cleanroom, MLCC water-treatment, and PFAS-compliant filtration.
This can be read as an effort to offset slowing demand in the legacy air-purifier and automotive filter markets through entry into new markets, though the revenue contribution remains unconfirmed at this early stage.
The company holds roughly 70% share of Korea's home air-purifier filter market, with major appliance makers Samsung Electronics, LG Electronics and Coway as customers. Its vertically integrated production, spanning MB raw media to finished filters, provides cost-response capability.
The capital-intensive nature of the industry, which limits new entrants, also creates an oligopolistic structure favorable to incumbents.
The debt ratio rose for three straight years, from 238.3% in 2023 to 319.5% in 2024 and 343.8% in 2025. This is the highest level in the past four fiscal years, warranting attention to financial soundness. Whether the earnings recovery translates into balance-sheet improvement remains to be confirmed.
Cumulative owners' net income over the trailing four quarters from 2025Q3 to 2026Q2 stood at negative KRW 2.014 billion, still in the red. Despite the return to profit in 2026Q1-Q2, this has not fully offset the large losses of 2025H2. Confirming additional quarters of results will be needed before full normalization can be established.
The legacy growth engines of home-appliance and automotive filters have reportedly entered a demand slowdown. Revenue of KRW 84.6 billion in 2024 fell from KRW 92.5 billion in 2023 and shows stalled growth even compared to KRW 86.0 billion in 2022. Until new businesses generate meaningful revenue, weakness in the core business could weigh on results.
A factory accident in the second half of 2025 is understood to have directly hit revenue and operating profit in Q3 and Q4. A recurrence of similar equipment or safety issues could again widen production disruption and earnings volatility. The effectiveness of utilization management and safety systems could be key to future earnings stability.
The AI data center, semiconductor cleanroom, MLCC and PFAS filter businesses remain at an early reference-acquisition stage, with supply scale and customer names not specifically disclosed. A related report also assessed that it will take time for these new businesses to translate into earnings improvement. If revenue contribution is delayed relative to investment, financial strain could increase.
The debt ratio climbed to 343.8% in 2025, and consecutive net losses have shrunk total equity from KRW 27.18 billion in 2022 to KRW 16.87 billion in 2025. Given that only 6.5 million of the 20 million authorized shares have been issued, the possibility of equity dilution in future capital raises cannot be ruled out. If the pace of balance-sheet improvement remains slow, the cost burden of external financing could increase.
Check the Q3 2026 quarterly report to confirm whether the profit-turnaround trend seen in 2026Q1-Q2 continued into Q3.
Watch for whether additional supply contracts or revenue recognition materialize for AI data center, semiconductor cleanroom, MLCC and PFAS-compliant filter products.
Check the FY2026 business and audit reports for confirmed annual results, whether the debt ratio and balance sheet improved, and whether dividends resume.
Monitor subsequent disclosures or news for any recurrence of factory accidents, normalization of utilization rates, and improvements to safety management systems.
Clean & Science maintains a solid business base with roughly 70% share of Korea's home air-purifier filter market, but its results were significantly disrupted by a 2025H2 factory accident before showing a recovery with two consecutive profitable quarters in the first half of 2026.
However, cumulative owners' net income over the trailing four quarters remains negative, and the debt ratio has risen steadily from 238.3% in 2023 to 343.8% in 2025, warranting attention on the balance sheet side.
New businesses in AI data center, semiconductor cleanroom, MLCC and PFAS-compliant filters are at an early reference-acquisition stage, with the timing and scale of revenue contribution not yet confirmed.
Against a backdrop where slowing demand in legacy appliance and automotive filter markets coexists with growth potential in new businesses, upcoming quarterly results and the concretization of new-business supply contracts will likely be key variables in gauging the durability of the recovery.
Dividends have not been paid in recent years, so any change on the shareholder return front is also worth watching. This report contains no investment opinion or buy/sell recommendation and is provided for informational purposes only.
Report written 2026-09-05 · Data as of 2026-09-04
This content is AI analysis of market data and web search results, provided for information only. It is not a solicitation or recommendation to invest. Investment decisions and their consequences are the investor's own responsibility. Data may be delayed or contain errors.