Diamond Hill Capital, an investment management company, released its “Mid Strategy” fourth-quarter 2025 investor letter. A copy of the letter can be downloaded here. The fourth quarter posted another period of favorable gains for equity markets, with small and large cap positions being stronger performers, returning 2.19% and 2.41%. While the mid-cap range was a relative laggard, with the Russell Mid Cap Index returning 0.16%. The Strategy returned 3.65% (net) in Q4, compared to 0.16% return for the Russell Midcap Index. YTD, the strategy returned 13.47%, outperforming the 10.60% return for the Index. In 2025, AI-related spending remained a key driver in equity markets, though December saw a pause as investors became more cautious about AI developments and potential market bubbles. Given the elevated valuation in the equity market, the Strategy is well-positioned for ongoing levels of heightened uncertainty going forward. Please review the Strategy’s top five holdings to gain insights into their key selections for 2025.
In its fourth-quarter 2025 investor letter, Diamond Hill Mid Strategy highlighted Ciena Corporation (NYSE:CIEN) as one of its leading contributors. Ciena Corporation (NYSE:CIEN) is a leading network technology company that provides hardware, software, and services for various network operators. On March 17, 2026, Ciena Corporation (NYSE:CIEN) stock closed at $370.05 per share. One-month return of Ciena Corporation (NYSE:CIEN) was 19.00%, and its shares gained 461.53% over the past 52 weeks. Ciena Corporation (NYSE:CIEN) has a market capitalization of $52.349 billion.
Diamond Hill Mid Strategy stated the following regarding Ciena Corporation (NYSE:CIEN) in its fourth quarter 2025 investor letter:
“Ciena Corporation (NYSE:CIEN), a networking systems company, saw shares increase meaningfully during the quarter amid optimism around hyperscaler and AI-related demand. The company has also benefited from growing cloud spending, which has supported its pluggables and data interconnect business.”
Ciena Corporation (NYSE:CIEN) is not on our list of 40 Most Popular Stocks Among Hedge Funds Heading Into 2026. According to our database, 71 hedge fund portfolios held Ciena Corporation (NYSE:CIEN) at the end of the fourth quarter, compared to 70 in the previous quarter. Ciena Corporation (NYSE:CIEN) delivered revenue of $1.43 billion in the first quarter of fiscal 2026, its highest ever and at the top end of the guidance, reflecting strong execution across the business. While we acknowledge the risk and potential of Ciena Corporation (NYSE:CIEN) as an investment, our conviction lies in the belief that some AI stocks hold greater promise for delivering higher returns and doing so within a shorter time frame. If you are looking for an AI stock that is more promising than Ciena Corporation (NYSE:CIEN) and that has 10,000% upside potential, check out our report about this cheapest AI stock.
In another article, we covered Ciena Corporation (NYSE:CIEN) and shared Madison Small Cap Fund’s views on the company. In addition, please check out our hedge fund investor letters Q4 2025 page for more investor letters from hedge funds and other leading investors.
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Disclosure: None. This article is originally published at Insider Monkey.
