Shannon River Fund Management LLC: RAMBUS INC DEL (RMBS): Quarterly 13F Position History
As of Q1 2026, Shannon River Fund Management LLC reported 333,817 shares of RAMBUS INC DEL (RMBS), worth $28.7M and representing 5.5% of its 13F equity book. Quarter-over-quarter share count change: + 333,817 (re-initiated) . The position first appeared in Q3 2021 and has been disclosed across 19 13F-HR filings in Pactolio's tracked window.
- 333,817Shares Held (Latest Filing)
- $28.7MReported Market Value (Latest Filing)
- 5.5%Portfolio Weight (% of 13F Equity Book)
- +333,817Quarter-over-Quarter Share Change
- +$28.7MQuarter-over-Quarter Value Change
- 930,973Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 19 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q1 2026 | 333,817 | +333,817 | — | $28.7M | 5.5% | $86.0 |
| Q4 2025 | 0 | 0 | — | $0 | 0.0% | — |
| Q3 2025 | 0 | 0 | — | $0 | 0.0% | — |
| Q2 2025 | 0 | 0 | — | $0 | 0.0% | — |
| Q1 2025 | 0 | 0 | — | $0 | 0.0% | — |
| Q4 2024 | 0 | 0 | — | $0 | 0.0% | — |
| Q3 2024 | 0 | 0 | — | $0 | 0.0% | — |
| Q2 2024 | 0 | 0 | — | $0 | 0.0% | — |
| Q1 2024 | 0 | 0 | — | $0 | 0.0% | — |
| Q4 2023 | 0 | 0 | — | $0 | 0.0% | — |
| Q3 2023 | 0 | 0 | — | $0 | 0.0% | — |
| Q2 2023 | 0 | 0 | — | $0 | 0.0% | — |
| Q1 2023 | 0 | 0 | — | $0 | 0.0% | — |
| Q4 2022 | 0 | 739,988 | -100.0% | $0 | 0.0% | — |
| Q3 2022 | 739,988 | 170,568 | -18.7% | $18.8M | 8.1% | $25.4 |
| Q2 2022 | 910,556 | +128,701 | +16.5% | $19.6M | 5.6% | $21.5 |
| Q1 2022 | 781,855 | 149,118 | -16.0% | $24.9M | 3.2% | $31.9 |
| Q4 2021 | 930,973 | +193,000 | +26.2% | $27.4M | 2.8% | $29.4 |
| Q3 2021 | 737,973 | — | — | $16.4M | 1.4% | $22.2 |
Methodology & FAQ
How This Position History Is Sourced
Each row is one SEC Form 13F-HR filing disclosing this position. Share count, market value, and reported quarter are taken verbatim from the filing; portfolio weight is recomputed against the same filing's total reported equity book. Implied price-per-share is market value divided by shares — a quarter-end mark, not the manager's cost basis. See the full methodology document for the normalization rules.
When did Shannon River Fund Management LLC first disclose a RMBS position in 13F-HR filings?
Shannon River Fund Management LLC first reported RAMBUS INC DEL (RMBS) on its 13F-HR filing for the period ending 2021-09-30 (Q3 2021). The position has appeared on 19 reported quarters within Pactolio's tracked window.
What was Shannon River Fund Management LLC's most recent quarter-over-quarter share-count change in RMBS?
Between Q4 2025 and Q1 2026, Shannon River Fund Management LLC added 333,817 shares of RMBS (re-initiated), bringing the total reported position to 333,817 shares at a market value of $28.7M.
Does the implied price-per-share represent Shannon River Fund Management LLC's cost basis in RMBS?
No. The implied price-per-share column is the 13F-HR reported market value divided by reported share count on the filing date (end of quarter). It is a quarter-end mark, not a cost basis or transaction price. Use it as a sanity check on the value column, not as an indicator of the manager's entry or exit price.