Metalúrgica Riosulense S.A

What it is

Metalúrgica Riosulense manufactures engine components for light vehicles, utility vehicles, trucks, agricultural machinery, motorcycles, and products for railway and marine transportation in Brazil. Its catalogue runs to more than 5,000 items — pistons, camshafts, cylinder liners, valve guides, and more — sold both directly to vehicle makers as original equipment and through the independent spare-parts market.

The company supplies parts to vehicle assemblers and exports to more than 25 countries, with customers spread across Latin America, Europe, North America, Asia, and Oceania. In 2012 it opened a cylinder-liner factory and in 2014 became the first foundry in Brazil to earn the international Transportation and Power Generation programme certificate.

Who owns it

Metalúrgica Riosulense was founded in 1946 by João Stramosk in Rio do Sul, Santa Catarina. The Stramosk family has controlled the business across three generations.

Insiders hold roughly 57% of the shares (structured data), while minority shareholders hold approximately 24% of the company, with institutions accounting for about 21% (structured data). The free float is thin, which means the shares trade in small daily volumes.

João Stramosk Filho serves as Chairman of the Board of Directors, a role he assumed in May 2018. Carlos Henrique Stramosk has been a board member since 2003; José Eduardo Stramosk joined the board in May 2018.

The board is also a family meeting: multiple Stramosk names hold every director seat save one reserved for minority shareholders.

Who runs it

Luis Stramosk serves as Chief Executive Officer (Diretor Presidente) of Metalúrgica Riosulense. He belongs to the same family that has run the business since its founding, keeping strategic decisions tightly held.

The CFO’s name and the specific names of any other C-suite executives beyond the board are not disclosed in available public sources.

The most recent material event filed at B3 was a “Fato Relevante” — a material-fact disclosure — dated 9 June 2026, the substance of which had not been made publicly available in aggregated sources at the time of writing; readers should check the company’s investor-relations page directly.

The money, in plain words

Revenue has grown every year in this data set: BRL 341.4 (US$66)M in 2023, BRL 380.8 (US$74)M in 2024, BRL 420.5 (US$82)M in 2025 — a compound pace of roughly 11% a year (our calculation). The company keeps about 15 cents of profit from every real of sales — a net profit margin of 15.0%, which is well above the global auto-parts industry median of around 5–7%.

For every real that owners have put into the business, it earns back roughly 23 cents a year — a return on equity of 23.3%, strong for a manufacturer. The balance sheet is close to debt-free: total borrowings of BRL 32.2 (US$6)M sit against only BRL 2.4 (US$0.47)M in cash, leaving net debt of BRL 29.8M (~US$5.8M; our calculation) — a trivial sum relative to BRL 274 (US$53)M of owners’ equity.

Yet the stock trades at only 5.65 times annual earnings (price-to-earnings ratio of 5.65×), a level that implies investors see limited growth or liquidity risks.

What it is doing now

Riosulense is building out additive manufacturing: through 3D-printing processes it now creates high-quality casting prototypes, shortening development cycles for new engine-part designs. Over the past year, the share paid out BRL 2.25 (US$0.44)in dividends, a dividend yield of approximately 7.6% on recent prices, a notable return for a small industrial company, though the EODHD trailing-twelve-month data does not capture a declared forward yield.

In 2019 the company rebranded its commercial face, shortening the trading name to simply “RIO.” It continues to invest in precision foundry capacity at its plant in Rio do Sul, where the site covers more than one million square metres of green land with over 27,000 m² of built factory floor.

What to watch

• Electric-vehicle transition. Riosulense’s entire product line serves internal-combustion engines. As Brazil’s vehicle fleet gradually electrifies, volumes in some legacy parts categories may plateau or shrink over the next decade.
• Family succession and governance. The Stramosk family controls a majority of shares and fills most board seats. Any change in that arrangement — or a decision to sell — would be the single largest event in this stock’s history.
• Export mix. With sales in more than 25 countries, a strong Brazilian real compresses the company’s competitiveness abroad; a weaker real does the opposite. BRL volatility is therefore a direct earnings lever.
• Liquidity. Daily trading in RSUL4 is very thin. Any large buyer or seller moves the price significantly, which amplifies both opportunity and risk for investors.
• The June 2026 “Fato Relevante.” A material-fact filing was submitted to B3 on 9 June 2026 — its content warrants close reading as it may signal a corporate event, regulatory matter, or strategic shift.

This is news, not investment advice.