Comfort Systems USA, Inc.
MX ˙ BMV ˙ US1999081045
SecurityMX:FIX / Comfort Systems USA, Inc.
InstitutionJane Street Group, Llc
Latest Disclosed Ownership3,463 shares
Latest Disclosed Value $ 4,775,442
Jane Street Group, Llc ownership in FIX / Comfort Systems USA, Inc.

On May 12, 2026 - Jane Street Group, Llc filed a 13F-HR form disclosing ownership of 3,463 shares of Comfort Systems USA, Inc. (MX:FIX) valued at $4,775,442 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 2,757 shares of Comfort Systems USA, Inc.. This represents a change in shares of 25.61% during the quarter.

Jane Street Group, Llc has a history of taking positions in derivatives of the underlying security (FIX) in the form of stock options. The firm currently holds call options representing 138,000 of underlying shares valued at $190,300,620 USD and put options representing 151,300 of underlying shares valued at $208,641,187 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.

MX:FIX / Comfort Systems USA, 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)
2026-05-12 2026-03-31 13F COMFORT SYS USA COM 199908104 3,463 706 25.61 4,775 85.58 0.0003
2026-02-12 2025-12-31 13F COMFORT SYS USA COM 199908104 2,757 -83,744 -96.81 2,573 -96.40 0.0004
2025-11-14 2025-09-30 13F COMFORT SYS USA COM 199908104 86,501 54,322 168.81 71,379 313.69 0.0109
2025-08-14 2025-06-30 13F COMFORT SYS USA COM 199908104 32,179 -12,231 -27.54 17,255 20.54 0.0034
2025-05-19 2025-03-31 13F/A-1 COMFORT SYS USA COM 199908104 44,410 -8,224 -15.62 14,315 -35.87 0.0036
2025-05-14 2025-03-31 13F COMFORT SYS USA COM 199908104 44,410 -8,224 14,315 0.0030
2025-02-14 2024-12-31 13F COMFORT SYS USA COM 199908104 52,634 -36,563 -40.99 22,320 -35.90 0.0048
2024-11-15 2024-09-30 13F COMFORT SYS USA COM 199908104 89,197 -175,308 -66.28 34,818 -56.72 0.0077
2024-08-15 2024-06-30 13F COMFORT SYS USA COM 199908104 264,505 251,567 1,944.40 80,441 1,857.20 0.0184
2024-05-16 2024-03-31 13F COMFORT SYS USA COM 199908104 12,938 -34,587 -72.78 4,111 -57.95 0.0009
2024-02-15 2023-12-31 13F COMFORT SYS USA COM 199908104 47,525 33,928 249.53 9,774 321.84 0.0025
2023-11-15 2023-09-30 13F COMFORT SYS USA COM 199908104 13,597 -15,780 -53.72 2,317 -51.96 0.0007
2023-08-14 2023-06-30 13F COMFORT SYS USA COM 199908104 29,377 9,729 49.52 4,824 68.22 0.0016
2023-05-16 2023-03-31 13F COMFORT SYS USA COM 199908104 19,648 30 0.15 2,868 27.03 0.0012
2023-02-15 2022-12-31 13F COMFORT SYS USA COM 199908104 19,618 8,996 84.69 2,258 118.28 0.0010
2022-11-15 2022-09-30 13F COMFORT SYS USA COM 199908104 10,622 2,474 30.36 1,034 52.51 0.0005
2022-08-16 2022-06-30 13F COMFORT SYS USA COM 199908104 8,148 8,148 678 0.0003
2022-05-17 2022-03-31 13F COMFORT SYS USA COM 199908104 0 -3,208 -100.00 0 -100.00
2022-02-15 2021-12-31 13F COMFORT SYS USA COM 199908104 3,208 84 2.69 317 42.15 0.0001
2021-11-16 2021-09-30 13F COMFORT SYS USA COM 199908104 3,124 -31,875 -91.07 223 -91.91 0.0001
2021-08-16 2021-06-30 13F COMFORT SYS USA COM 199908104 34,999 16,991 94.35 2,758 104.90 0.0011
2021-05-18 2021-03-31 13F COMFORT SYS USA COM 199908104 18,008 13,541 303.13 1,346 472.77 0.0007
2021-02-17 2020-12-31 13F COMFORT SYS USA COM 199908104 4,467 4,467 235 0.0001
2019-08-14 2019-06-30 13F COMFORT SYS USA COM 199908104 0 -6,846 -100.00 0 -100.00
2019-05-16 2019-03-31 13F COMFORT SYS USA COM 199908104 6,846 6,846 359 0.0006
2019-02-14 2018-12-31 13F COMFORT SYS USA COM 199908104 0 -8,307 -100.00 0 -100.00
2018-11-14 2018-09-30 13F COMFORT SYS USA COM 199908104 8,307 8,307 469 0.0009
2018-02-15 2017-12-31 13F COMFORT SYS USA COM 199908104 0 -7,540 -100.00 0 -100.00
2017-11-14 2017-09-30 13F COMFORT SYS USA COM 199908104 7,540 7,540 269 0.0009
2016-05-17 2016-03-31 13F COMFORT SYS USA COM 199908104 0 -14,707 -100.00 0 -100.00
2016-02-16 2015-12-31 13F COMFORT SYS USA COM 199908104 14,707 -6,378 -30.25 418 -27.30 0.0026
2015-11-16 2015-09-30 13F COMFORT SYS USA COM 199908104 21,085 21,085 575 0.0036
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
(%)
2026-05-12 2026-03-31 13F COMFORT SYS USA COM Call 138,000 396.40 190,301 633.47 n/a n/a n/a
2026-02-12 2025-12-31 13F COMFORT SYS USA COM Call 27,800 247.50 25,945 293.05 n/a n/a n/a
2025-11-14 2025-09-30 13F COMFORT SYS USA COM Call 8,000 -51.81 6,601 -25.84 n/a n/a n/a
2025-08-14 2025-06-30 13F COMFORT SYS USA COM Call 16,600 -33.33 8,901 10.90 n/a n/a n/a
2025-05-19 2025-03-31 13F/A COMFORT SYS USA COM Call 24,900 7.79 8,026 -18.06 n/a n/a n/a
2025-05-14 2025-03-31 13F COMFORT SYS USA COM Call 24,900 8,026 n/a n/a n/a
2025-02-14 2024-12-31 13F COMFORT SYS USA COM Call 23,100 104.42 9,796 122.11 n/a n/a n/a
2024-11-15 2024-09-30 13F COMFORT SYS USA COM Call 11,300 334.62 4,411 458.23 n/a n/a n/a
2024-08-15 2024-06-30 13F COMFORT SYS USA COM Call 2,600 -87.85 791 -88.38 n/a n/a n/a
2024-05-16 2024-03-31 13F COMFORT SYS USA COM Call 21,400 94.55 6,799 200.53 n/a n/a n/a
2024-02-15 2023-12-31 13F COMFORT SYS USA COM Call 11,000 -46.08 2,262 -34.93 n/a n/a n/a
2023-11-15 2023-09-30 13F COMFORT SYS USA COM Call 20,400 67.21 3,476 73.54 n/a n/a n/a
2023-08-14 2023-06-30 13F COMFORT SYS USA COM Call 12,200 2,003 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
(%)
2026-05-12 2026-03-31 13F COMFORT SYS USA COM Put 151,300 296.07 208,641 485.23 n/a n/a n/a
2026-02-12 2025-12-31 13F COMFORT SYS USA COM Put 38,200 229.31 35,652 272.45 n/a n/a n/a
2025-11-14 2025-09-30 13F COMFORT SYS USA COM Put 11,600 103.51 9,572 213.22 n/a n/a n/a
2025-08-14 2025-06-30 13F COMFORT SYS USA COM Put 5,700 14.00 3,056 89.70 n/a n/a n/a
2025-05-19 2025-03-31 13F/A COMFORT SYS USA COM Put 5,000 212.50 1,612 137.61 n/a n/a n/a
2025-05-14 2025-03-31 13F COMFORT SYS USA COM Put 5,000 1,612 n/a n/a n/a
2025-02-14 2024-12-31 13F COMFORT SYS USA COM Put 1,600 -23.81 678 -17.22 n/a n/a n/a
2024-11-15 2024-09-30 13F COMFORT SYS USA COM Put 2,100 -4.55 820 22.42 n/a n/a n/a
2024-08-15 2024-06-30 13F COMFORT SYS USA COM Put 2,200 -69.44 669 -70.75 n/a n/a n/a
2024-05-16 2024-03-31 13F COMFORT SYS USA COM Put 7,200 12.50 2,288 73.78 n/a n/a n/a
2024-02-15 2023-12-31 13F COMFORT SYS USA COM Put 6,400 433.33 1,316 545.10 n/a n/a n/a
2023-11-15 2023-09-30 13F COMFORT SYS USA COM Put 1,200 204 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.