REGN
Regeneron Pharmaceuticals Inc
Regeneron Pharmaceuticals Inc historical holders
total: 8
Longleaf Partners Regeneron Pharmaceuticals Inc transactions over time
- Total transactions:
- 5
- New positions:
- 1
- Added:
- 1
- Reduced:
- 3
- Held since:
- 2025 Q1
- Held for:
- 5 quarters
- Latest activity:
- 2026 Q1
Mason Hawkins has been an institutional investor in Regeneron Pharmaceuticals Inc (REGN) since 2025 Q1. According to 2026 Q1 report, Mason Hawkins holds 65,506 shares with a market value of roughly $50.61M representing 4.81% of their equity portfolio. The fund/company first acquired REGN in 2025 Q1, initially purchasing 79,873 shares. Since the initial investment, Longleaf Partners has made 4 more transactions in this position.
Does Mason Hawkins still hold REGN?
Yes, Mason Hawkins continues to hold Regeneron Pharmaceuticals Inc (REGN). According to their 2026 Q1 report, they maintain a position of 65,506 shares valued at approximately $50.61M, representing 4.81% of their equity portfolio.
When did Mason Hawkins first invest in REGN?
Mason Hawkins first invested in Regeneron Pharmaceuticals Inc (REGN) in 2025 Q1 at the reported quarter-end price of $634.23 per share, acquiring 79,873 shares in their initial purchase.
What is Mason Hawkins's average cost basis for REGN?
Based on historical transaction data, Mason Hawkins's estimated cost basis for Regeneron Pharmaceuticals Inc (REGN) is approximately $602.83 per share. This represents their average reported price* across all buy transactions.
Estimated cost basis*
- Weighted AVG buy price:
- $602.83
- Weighted AVG sell price:
- $711.90
REGN transactions history by Longleaf Partners
5 results
| Period |
% of portfolio |
Shares held after* |
Reported price* |
Value* |
% (shares) of activity |
% change to portfolio |
|---|---|---|---|---|---|---|
|
2026 Q1
|
4.81%
|
65,506
|
$772.64
|
$50,612,556
|
-24.10% (-20,799)
|
-1.46%
|
|
2025 Q4
|
6.07%
|
86,305
|
$771.87
|
$66,616,240
|
-12.55% (-12,383)
|
-0.84%
|
|
2025 Q3
|
4.90%
|
98,688
|
$562.27
|
$55,489,302
|
-11.96% (-13,407)
|
-0.64%
|
|
2025 Q2
|
4.98%
|
112,095
|
$525.00
|
$58,849,875
|
+40.34% (+32,222)
|
+1.43%
|
|
2025 Q1
|
4.36%
|
79,873
|
$634.23
|
$50,657,853
|
new
|
+4.36%
|
* Shares, change to shares, sold shares, shares held after: split-adjusted.
* Reported price: this doesn't represent the actual buy or sell price. It is the split-adjusted price of the security as of the last day of the reported period.
If the security is completely sold out, we show the reported split-adjusted price prior to the actual period.
If the security is completely sold out, we show the reported split-adjusted price prior to the actual period.
* Estimated cost basis: based on "Reported price*" (not earlier than 2013 Q2). Calculation starts from the latest "new buy" activity to the latest "close out" activity (if any).
* Value or Price: If the security is completely sold out, we show the reported value (or price) prior to the actual period.
* New buy or own: this means there is no earlier reporting (for us or in general). So we can't know if the actual purchase of the security happened at the reported period or earlier.