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RBBN

Ribbon Communications Inc.

Company with tickers: RBBN

CIK
1708055
CUSIP
762544104
Shares Outstanding
176,139,067
13F Activity (30d)
87 filings 82 filers

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 149
Total Value: $274,409,880
Total Shares: 129,438,670
Showing 1–100 of 152 holdings by value · page 1 of 2

Institutional Ownership Trend

25 quarters

Holder Concentration

Across 149 13F filers · Δ vs Dec 31, 2025
Top Holder
40.2%
Jun 2023 → Mar 2026 · range 40.0% – 42.5%
+0.1 pts
Top 5
69.9%
Jun 2023 → Mar 2026 · range 69.9% – 77.0%
−1.9 pts
Top 10
83.0%
Jun 2023 → Mar 2026 · range 83.0% – 87.9%
−2.3 pts
HHI
1,935
Jun 2023 → Mar 2026 · range 1,935 – 2,182
Moderately concentrated−17

Quarterly Activity

vs Dec 31, 2025
New
35
Increased
52
Decreased
43
Sold Out
41
Unchanged
19
Holder count: -6
Institutional value: -26.6%
Shares held: -0.3%

Top Buyers

vs Dec 31, 2025
Institution Added Now Holds Open

Top Sellers

vs Dec 31, 2025
Institution Sold Now Holds Open

Top New Positions

vs Dec 31, 2025
Institution Acquired Value (USD) Open

Top Sold-Out Positions

vs Dec 31, 2025
Institution Previously Held Last Value (USD) Open
Showing 100 of 152
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Holder Value (USD) % of 13F Shares Open