Longleaf Partners REGN trades
Mason Hawkins
Mason Hawkins Regeneron Pharmaceuticals Inc stake
total: 53
Trades details
- Total transactions:
- 6
- New positions:
- 1
- Added:
- 2
- Reduced:
- 3
- Held since:
- 2025 Q1
- Held for:
- 6 quarters
- Latest activity:
- 2026 Q2
According to 2026 Q2 report, Mason Hawkins holds 79,898 Regeneron Pharmaceuticals Inc (REGN) shares with a market value of roughly $49.82M accounting for 4.74% of the overall portfolio. To date, the estimated cost basis is nearly $605.19 for "buy" trades and estimated average "sell" price is $711.9. Longleaf Partners first purchased REGN in 2025 Q1, initially acquiring 79,873 shares. Since the initial investment in Regeneron Pharmaceuticals Inc (REGN), Longleaf Partners has made 5 more transactions.
When did Mason Hawkins buy Regeneron Pharmaceuticals Inc (REGN)?
Mason Hawkins first invested in Regeneron Pharmaceuticals Inc (REGN) in 2025 Q1 at the reported quarter-end price of $634.23 per share.
What's the cost basis of Longleaf Partners's REGN stake?
The estimated cost basis for Regeneron Pharmaceuticals Inc (REGN) stake is around $605.19 per share. This represents their average reported price* across all buy transactions
Estimated cost basis*
- Weighted AVG buy price:
- $605.19
- Weighted AVG sell price:
- $711.90
Mason Hawkins's historical trades in Regeneron Pharmaceuticals Inc
6 results
| Period |
% of portfolio |
Shares held after* |
Reported price* |
Value* |
% (shares) of activity |
% change to portfolio |
|---|---|---|---|---|---|---|
|
2026 Q2
|
4.74%
|
79,898
|
$623.54
|
$49,819,599
|
+21.97% (+14,392)
|
+0.85%
|
|
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.