CIEN
Ciena Corp
4 super-investors hold CIEN worth a combined $371M. The largest position: Stephen Mandel at 2.5% of their portfolio. This quarter the cohort logged 1 buy and 0 sells on the name. Cohort Conviction Score: 28 — ranked #467 of 724 scored stocks. Conviction rising: 1 more super-investor hold it than in 2025Q4.
Why super-investors own CIEN
Stephen Mandel's new position — $314M, representing 2.5% of his portfolio — dominates the cohort's $371M combined stake in CIEN and is the only meaningful conviction signal here. Mandel's entry in 2026Q1 is the defining event; the three other holders (Greenblatt, Mairs & Power, First Eagle) each carry negligible allocations under 0.1% of their respective portfolios. The ownership history tells a thin story: the cohort had one brief owner two quarters ago, then zero, and now Mandel alone re-establishes a foothold. With no additions, trims, or exits among the remaining holders, interest is technically rising but is almost entirely dependent on a single new entrant rather than any broadening cohort conviction.
AI-synthesized from 13F filings. Not investment advice.
Cohort owners over time
2021Q4 → 2026Q1How many of the cohort members held this stock each quarter.
Owners (4) · click any column to sort
| #↑ | Manager | % Port. | History | Value | Shares |
|---|---|---|---|---|---|
| 1 | Stephen Mandel | 2.5% | 2q | $314M | 809,522 |
| 2 | Joel Greenblatt | <0.1% | 38q | $55M | 140,435 |
| 3 | Mairs & Power Funds | <0.1% | 4q | $1M | 2,800 |
| 4 | First Eagle Investment Management | <0.1% | 10q | $1M | 2,600 |
Owners of CIEN also hold
Recent activity (1)
| Manager | Move | % Port. | Δ Shares | Value | Filed |
|---|---|---|---|---|---|
| Stephen Mandel | NEW | 2.5% | +100% | $314M | May 15, 2026 |
Long US equity 13F-HR filings only. CUSIP 171779309. Not investment advice.