Heartland Advisors, an investment management company, released its “Heartland Value Plus Fund” third-quarter 2025 investor letter. A copy of the letter can be downloaded here. The third quarter proved to be robust for small caps, signaling improved demand dynamics. The Russell 2000® Index was up 12.39% in the quarter, outperforming the S&P 500 Index, which rose 8.12%. The fund returned 8.51% in the third quarter compared to a 12.60% gain for the Russell 2000® Value Index. In addition, you can check the fund’s top 5 holdings to determine its best picks for 2025.
In its third-quarter 2025 investor letter, Heartland Value Plus Fund highlighted stocks such as Materion Corporation (NYSE:MTRN). Materion Corporation (NYSE:MTRN) is an advanced engineered materials manufacturer. The one-month return of Materion Corporation (NYSE:MTRN) was 3.07%, and its shares gained 11.67% of their value over the last 52 weeks. On October 10, 2025, Materion Corporation (NYSE:MTRN) stock closed at $118.10 per share, with a market capitalization of $2.448 billion.
Heartland Value Plus Fund stated the following regarding Materion Corporation (NYSE:MTRN) in its third quarter 2025 investor letter:
“Our top performer for the quarter was Materion Corporation (NYSE:MTRN), a vertically integrated producer of high-performance advanced engineered materials based on beryllium, a rare metal that is one-third lighter than aluminum but has six times the stiffness of steel.
Materion Corporation (NYSE:MTRN) is not on our list of 30 Most Popular Stocks Among Hedge Funds. According to our database, 24 hedge fund portfolios held Materion Corporation (NYSE:MTRN) at the end of the second quarter, up from 22 in the previous quarter. While we acknowledge the potential of Materion Corporation (NYSE:MTRN) as an investment, we believe certain AI stocks offer greater upside potential and carry less downside risk. If you’re looking for an extremely undervalued AI stock that also stands to benefit significantly from Trump-era tariffs and the onshoring trend, see our free report on the best short-term AI stock.
