Repligen Corporation
US ˙ NasdaqGS ˙ US7599161095

SecurityRGEN / Repligen Corporation
InstitutionCitigroup Inc
Latest Disclosed Ownership36,356 shares
Latest Disclosed Value $ 4,283,464
Citigroup Inc ownership in RGEN / Repligen Corporation

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 36,356 shares of Repligen Corporation (US:RGEN) valued at $4,283,464 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 83,752 shares of Repligen Corporation. This represents a change in shares of -56.59% during the quarter. The current value of the position is $4,425,616 USD.

Citigroup Inc has a history of taking positions in derivatives of the underlying security (RGEN) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

RGEN / Repligen Corporation Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-11 2026-03-31 13F REPLIGEN COM 759916109 36,356 -47,396 -56.59 4,283 -68.79 0.0018
2026-02-13 2025-12-31 13F REPLIGEN COM 759916109 83,752 32,183 62.41 13,724 99.09 0.0061
2025-11-10 2025-09-30 13F REPLIGEN COM 759916109 51,569 -35,551 -40.81 6,893 -36.38 0.0031
2025-08-11 2025-06-30 13F REPLIGEN COM 759916109 87,120 29,818 52.04 10,836 48.61 0.0053
2025-05-12 2025-03-31 13F REPLIGEN COM 759916109 57,302 -26,824 -31.89 7,291 -39.79 0.0037
2025-02-12 2024-12-31 13F REPLIGEN COM 759916109 84,126 -9,272 -9.93 12,109 -12.88 0.0072
2024-11-12 2024-09-30 13F REPLIGEN COM 759916109 93,398 1,054 1.14 13,899 19.41 0.0081
2024-08-12 2024-06-30 13F REPLIGEN COM 759916109 92,344 61,805 202.38 11,641 107.26 0.0075
2024-05-10 2024-03-31 13F REPLIGEN COM 759916109 30,539 -9,653 -24.02 5,617 -22.28 0.0037
2024-02-09 2023-12-31 13F REPLIGEN COM 759916109 40,192 3,887 10.71 7,227 25.19 0.0051
2023-12-06 2023-09-30 13F/A-1 REPLIGEN COM 759916109 36,305 -9,281 -20.36 5,773 -10.48 0.0043
2023-11-09 2023-09-30 13F REPLIGEN COM 759916109 36,305 -9,281 5,773 0.0017
2023-08-10 2023-06-30 13F REPLIGEN COM 759916109 45,586 2,575 5.99 6,449 -10.95 0.0042
2023-05-11 2023-03-31 13F REPLIGEN COM 759916109 43,011 1,051 2.50 7,241 1.93 0.0051
2023-02-09 2022-12-31 13F REPLIGEN COM 759916109 41,960 -3,012 -6.70 7,104 -15.58 0.0057
2022-11-10 2022-09-30 13F REPLIGEN COM 759916109 44,972 15,966 55.04 8,415 78.66 0.0060
2022-08-10 2022-06-30 13F REPLIGEN COM 759916109 29,006 -6,414 -18.11 4,710 -29.32 0.0035
2022-05-12 2022-03-31 13F REPLIGEN COM 759916109 35,420 21,880 161.60 6,664 85.78 0.0041
2022-02-10 2021-12-31 13F REPLIGEN COM 759916109 13,540 -1,976 -12.74 3,587 -20.00 0.0019
2021-11-10 2021-09-30 13F REPLIGEN COM 759916109 15,516 -3,855 -19.90 4,484 15.99 0.0026
2021-08-10 2021-06-30 13F REPLIGEN COM 759916109 19,371 10,764 125.06 3,866 131.22 0.0023
2021-05-13 2021-03-31 13F REPLIGEN COM 759916109 8,607 -14,587 -62.89 1,672 -62.38 0.0011
2021-02-11 2020-12-31 13F REPLIGEN COM 759916109 23,194 3,722 19.11 4,444 54.68 0.0026
2020-11-12 2020-09-30 13F REPLIGEN COM 759916109 19,472 -67,652 -77.65 2,873 -73.32 0.0019
2020-08-12 2020-06-30 13F REPLIGEN COM 759916109 87,124 65,055 294.78 10,769 405.59 0.0084
2020-05-12 2020-03-31 13F REPLIGEN COM 759916109 22,069 1,857 9.19 2,130 13.96 0.0019
2020-02-12 2019-12-31 13F REPLIGEN COM 759916109 20,212 -37,201 -64.80 1,869 -57.55 0.0014
2019-11-08 2019-09-30 13F REPLIGEN COM 759916109 57,413 41,193 253.96 4,403 215.85 0.0035
2019-08-12 2019-06-30 13F REPLIGEN COM 759916109 16,220 -12,223 -42.97 1,394 -17.02 0.0011
2019-05-13 2019-03-31 13F REPLIGEN COM 759916109 28,443 -52,120 -64.69 1,680 -60.46 0.0016
2019-02-12 2018-12-31 13F REPLIGEN COM 759916109 80,563 68,199 551.59 4,249 519.39 0.0043
2018-11-13 2018-09-30 13F REPLIGEN COM 759916109 12,364 8,802 247.11 686 308.33 0.0006
2018-08-10 2018-06-30 13F REPLIGEN COM 759916109 3,562 -221 -5.84 168 22.63 0.0002
2018-05-11 2018-03-31 13F REPLIGEN COM 759916109 3,783 -56,043 -93.68 137 -93.69 0.0001
2018-02-12 2017-12-31 13F REPLIGEN COM 759916109 59,826 11,453 23.68 2,170 17.11 0.0017
2017-11-13 2017-09-30 13F REPLIGEN COM 759916109 48,373 -4,668 -8.80 1,853 -15.70 0.0015
2017-08-11 2017-06-30 13F REPLIGEN COM 759916109 53,041 11,409 27.40 2,198 50.03 0.0020
2017-05-12 2017-03-31 13F REPLIGEN COM 759916109 41,632 -58,403 -58.38 1,465 -52.48 0.0013
2017-02-10 2016-12-31 13F REPLIGEN COM 759916109 100,035 70,132 234.53 3,083 241.42 0.0028
2016-11-10 2016-09-30 13F REPLIGEN COM 759916109 29,903 16,286 119.60 903 142.09 0.0008
2016-08-12 2016-06-30 13F REPLIGEN COM 759916109 13,617 -9,119 -40.11 373 -38.85 0.0004
2016-05-13 2016-03-31 13F REPLIGEN COM 759916109 22,736 20,079 755.70 610 713.33 0.0007
2016-02-12 2015-12-31 13F REPLIGEN COM 759916109 2,657 1,850 229.24 75 240.91 0.0001
2015-11-13 2015-09-30 13F REPLIGEN COM 759916109 807 349 76.20 22 15.79 0.0000
2015-08-13 2015-06-30 13F REPLIGEN COM 759916109 458 -490 -51.69 19 -34.48 0.0000
2015-05-14 2015-03-31 13F REPLIGEN COM 759916109 948 -4,902 -83.79 29 -75.21 0.0000
2015-02-17 2014-12-31 13F REPLIGEN COM 759916109 5,850 4,735 424.66 117 431.82 0.0001
2014-11-14 2014-09-30 13F REPLIGEN COM 759916109 1,115 -2,098 -65.30 22 -70.27 0.0000
2014-08-14 2014-06-30 13F REPLIGEN COM 759916109 3,213 -4,279 -57.11 74 -22.92 0.0001
2014-05-15 2014-03-31 13F REPLIGEN COM 759916109 7,492 -6,193 -45.25 96 -48.66 0.0001
2014-02-14 2013-12-31 13F REPLIGEN COM 759916109 13,685 7,547 122.96 187 175.00 0.0002
2013-11-14 2013-09-30 13F REPLIGEN COM 759916109 6,138 4,797 357.72 68 518.18 0.0001
2013-08-14 2013-06-30 13F REPLIGEN COM 759916109 1,341 1,341 11 0.0000
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2024-05-10 2024-03-31 13F REPLIGEN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-09 2023-12-31 13F REPLIGEN COM Call 23,000 4,135 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.