Montrose Environmental Group, Inc.
US ˙ NYSE ˙ US6151111019
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT

SecurityMEG / Montrose Environmental Group, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership222,587 shares
Latest Disclosed Value $ 4,872,429
Citadel Advisors Llc ownership in MEG / Montrose Environmental Group, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 222,587 shares of Montrose Environmental Group, Inc. (US:MEG) valued at $4,872,429 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 172,754 shares of Montrose Environmental Group, Inc.. This represents a change in shares of 28.85% during the quarter. The current value of the position is $4,928,076 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (MEG) in the form of stock options. The firm currently holds call options representing 46,200 of underlying shares valued at $1,011,318 USD and put 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.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

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.

MEG / Montrose Environmental Group, Inc. 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)
2026-05-15 2026-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 222,587 49,833 28.85 4,872 13.59 0.0007
2026-02-17 2025-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 172,754 -63,227 -26.79 4,289 -33.81 0.0006
2025-11-14 2025-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 235,981 55,790 30.96 6,480 64.30 0.0009
2025-08-14 2025-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 180,191 77,098 74.78 3,944 168.30 0.0007
2025-05-15 2025-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 103,093 -23,704 -18.69 1,470 -37.50 0.0003
2025-02-14 2024-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 126,797 -261,871 -67.38 2,352 -76.99 0.0004
2024-11-14 2024-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 388,668 347,244 838.27 10,222 453.98 0.0020
2024-08-14 2024-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 41,424 9,352 29.16 1,846 46.89 0.0004
2024-05-15 2024-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 32,072 -85,024 -72.61 1,256 -66.61 0.0002
2024-02-14 2023-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 117,096 -33,885 -22.44 3,762 -14.83 0.0008
2023-11-14 2023-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 150,981 17,209 12.86 4,418 -21.60 0.0009
2023-08-14 2023-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 133,772 94,439 240.10 5,634 301.57 0.0012
2023-05-15 2023-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 39,333 -10,489 -21.05 1,403 -36.54 0.0003
2023-02-14 2022-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 49,822 26,080 109.85 2,212 176.72 0.0005
2022-11-14 2022-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 23,742 -13,594 -36.41 799 -36.59 0.0002
2022-08-15 2022-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 37,336 -99,012 -72.62 1,260 -82.54 0.0003
2022-05-16 2022-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 136,348 -37,658 -21.64 7,217 -41.18 0.0015
2022-02-14 2021-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 174,006 45,368 35.27 12,270 54.50 0.0025
2021-11-15 2021-09-30 13F MONTROSE ENVIRONMENTAL GROUP Cmn 615111101 128,638 38,615 42.89 7,942 64.40 0.0017
2021-08-16 2021-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 90,023 58,202 182.90 4,831 202.50 0.0011
2021-05-21 2021-03-31 13F/A-1 MONTROSE ENVIRONMENTAL GROUP COM 615111101 31,821 -154,456 -82.92 1,597 -72.31 0.0004
2021-05-17 2021-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 31,821 -154,456 1,597 0.0004
2021-02-16 2020-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 186,277 172,165 1,219.99 5,767 1,616.37 0.0015
2020-11-16 2020-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM 615111101 14,112 14,112 336 0.0001
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
(%)
2026-05-15 2026-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 46,200 -0.65 1,011 -12.39 n/a n/a n/a
2026-02-17 2025-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 46,500 -11.93 1,155 -20.36 n/a n/a n/a
2025-11-14 2025-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 52,800 -18.27 1,450 2.48 n/a n/a n/a
2025-08-14 2025-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 64,600 37.15 1,414 110.73 n/a n/a n/a
2025-05-15 2025-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 47,100 140.31 672 84.85 n/a n/a n/a
2025-02-14 2024-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 19,600 -30.00 364 -50.68 n/a n/a n/a
2024-11-14 2024-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 28,000 18.14 736 -30.30 n/a n/a n/a
2024-08-14 2024-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 23,700 146.88 1,056 180.85 n/a n/a n/a
2024-05-15 2024-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 9,600 -20.66 376 -3.09 n/a n/a n/a
2024-02-14 2023-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 12,100 40.70 389 54.58 n/a n/a n/a
2023-11-14 2023-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 8,600 21.13 252 -16.05 n/a n/a n/a
2023-08-14 2023-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 7,100 -87.30 299 -85.00 n/a n/a n/a
2023-05-15 2023-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 55,900 1,896.43 1,994 1,507.26 n/a n/a n/a
2023-02-14 2022-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 2,800 -76.07 124 -68.53 n/a n/a n/a
2022-11-14 2022-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 11,700 -45.33 394 -45.43 n/a n/a n/a
2022-08-15 2022-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 21,400 13.23 722 -27.80 n/a n/a n/a
2022-05-16 2022-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 18,900 -43.75 1,000 -57.79 n/a n/a n/a
2022-02-14 2021-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 33,600 -16.42 2,369 -4.55 n/a n/a n/a
2021-11-15 2021-09-30 13F MONTROSE ENVIRONMENTAL GROUP Cmn Call 40,200 39.58 2,482 60.65 n/a n/a n/a
2021-08-16 2021-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 28,800 -68.59 1,545 -66.43 n/a n/a n/a
2021-05-21 2021-03-31 13F/A MONTROSE ENVIRONMENTAL GROUP COM Call 91,700 133.93 4,602 279.08 n/a n/a n/a
2021-05-17 2021-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 91,700 4,602 n/a n/a n/a
2021-02-16 2020-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Call 39,200 -15.70 1,214 9.57 n/a n/a n/a
2020-11-16 2020-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Call 46,500 1,108 n/a n/a n/a
Disclosed Put 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
(%)
2026-02-17 2025-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 0 -100.00 0 n/a n/a n/a
2025-11-14 2025-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 7,800 214 n/a n/a n/a
2025-08-14 2025-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 76,100 178.75 1,085 114.43 n/a n/a n/a
2025-02-14 2024-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 27,300 114.96 506 51.50 n/a n/a n/a
2024-11-14 2024-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 12,700 504.76 334 259.14 n/a n/a n/a
2024-08-14 2024-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 2,100 -76.40 94 -73.28 n/a n/a n/a
2024-05-15 2024-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 8,900 74.51 349 113.50 n/a n/a n/a
2024-02-14 2023-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 5,100 96.15 164 114.47 n/a n/a n/a
2023-11-14 2023-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 2,600 420.00 76 261.90 n/a n/a n/a
2023-08-14 2023-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 500 -90.74 21 -89.06 n/a n/a n/a
2023-05-15 2023-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 5,400 800.00 193 638.46 n/a n/a n/a
2023-02-14 2022-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 600 27 n/a n/a n/a
2022-08-15 2022-06-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-05-16 2022-03-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 5,100 37.84 270 3.45 n/a n/a n/a
2022-02-14 2021-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 3,700 -11.90 261 0.77 n/a n/a n/a
2021-11-15 2021-09-30 13F MONTROSE ENVIRONMENTAL GROUP Cmn Put 4,200 259 n/a n/a n/a
2021-05-21 2021-03-31 13F/A MONTROSE ENVIRONMENTAL GROUP COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-16 2020-12-31 13F MONTROSE ENVIRONMENTAL GROUP COM Put 13,000 -10.34 402 16.52 n/a n/a n/a
2020-11-16 2020-09-30 13F MONTROSE ENVIRONMENTAL GROUP COM Put 14,500 345 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.