Comfort Systems USA, Inc.
MX ˙ BMV ˙ US1999081045
SecurityMX:FIX / Comfort Systems USA, Inc.
InstitutionWalleye Trading LLC
Latest Disclosed Ownership1,251 shares
Latest Disclosed Value $ 1,725,116
Walleye Trading LLC ownership in FIX / Comfort Systems USA, Inc.

On May 8, 2026 - Walleye Trading LLC filed a 13F-HR form disclosing ownership of 1,251 shares of Comfort Systems USA, Inc. (MX:FIX) valued at $1,725,116 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 2,780 shares of Comfort Systems USA, Inc.. This represents a change in shares of -55.00% during the quarter.

Walleye Trading 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 1,600 of underlying shares valued at $2,206,384 USD and put options representing 1,200 of underlying shares valued at $1,654,788 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.

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)
2026-05-08 2026-03-31 13F COMFORT SYS USA COM 199908104 1,251 -1,529 -55.00 1,725 -33.50 0.0029
2026-02-13 2025-12-31 13F COMFORT SYS USA COM 199908104 2,780 -4,957 -64.07 2,595 -59.37 0.0037
2025-11-14 2025-09-30 13F COMFORT SYS USA COM 199908104 7,737 4,359 129.04 6,384 252.51 0.0097
2025-08-13 2025-06-30 13F COMFORT SYS USA COM 199908104 3,378 3,378 1,811 0.0033
2024-11-14 2024-09-30 13F COMFORT SYS USA COM 199908104 0 -122 -100.00 0 -100.00
2024-08-14 2024-06-30 13F COMFORT SYS USA COM 199908104 122 122 37 0.0001
2019-02-14 2018-12-31 13F COMFORT SYS USA COM 199908104 0 -120 -100.00 0 -100.00
2018-11-14 2018-09-30 13F COMFORT SYS USA COM 199908104 120 120 7 0.0000
2017-08-14 2017-06-30 13F COMFORT SYS USA COM 199908104 0 -500 -100.00 0 -100.00
2017-05-15 2017-03-31 13F COMFORT SYS USA COM 199908104 500 53 11.86 18 20.00 0.0001
2017-02-14 2016-12-31 13F COMFORT SYS USA COM 199908104 447 -189 -29.72 15 -21.05 0.0001
2016-11-14 2016-09-30 13F COMFORT SYS USA COM 199908104 636 636 0.00 19 0.0001
2016-08-15 2016-06-30 13F COMFORT SYS USA COM 199908104 0 -1,742 -100.00 0 -100.00
2016-05-16 2016-03-31 13F COMFORT SYS USA COM 199908104 1,742 -1,297 -42.68 55 -36.05 0.0005
2016-02-16 2015-12-31 13F COMFORT SYS USA COM 199908104 3,039 -2,361 -43.72 86 -41.50 0.0008
2015-11-16 2015-09-30 13F COMFORT SYS USA COM 199908104 5,400 4,300 390.91 147 488.00 0.0013
2015-08-14 2015-06-30 13F COMFORT SYS USA COM 199908104 1,100 1,100 25 0.0002
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
(%)
2026-05-08 2026-03-31 13F COMFORT SYS USA COM Call 1,600 -36.00 2,206 -5.44 n/a n/a n/a
2026-02-13 2025-12-31 13F COMFORT SYS USA COM Call 2,500 212.50 2,333 253.48 n/a n/a n/a
2025-11-14 2025-09-30 13F COMFORT SYS USA COM Call 800 0.00 660 54.21 n/a n/a n/a
2025-08-13 2025-06-30 13F COMFORT SYS USA COM Call 800 -61.90 429 -36.69 n/a n/a n/a
2025-05-14 2025-03-31 13F COMFORT SYS USA COM Call 2,100 677 n/a n/a n/a
2025-02-13 2024-12-31 13F COMFORT SYS USA COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-11-14 2024-09-30 13F COMFORT SYS USA COM Call 400 -20.00 156 2.63 n/a n/a n/a
2024-08-14 2024-06-30 13F COMFORT SYS USA COM Call 500 152 n/a n/a n/a
2017-02-14 2016-12-31 13F COMFORT SYS USA COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-11-14 2016-09-30 13F COMFORT SYS USA COM Call 4,900 157.89 144 132.26 n/a n/a n/a
2016-08-15 2016-06-30 13F COMFORT SYS USA COM Call 1,900 -20.83 62 -18.42 n/a n/a n/a
2016-05-16 2016-03-31 13F COMFORT SYS USA COM Call 2,400 76 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
(%)
2026-05-08 2026-03-31 13F COMFORT SYS USA COM Put 1,200 -14.29 1,655 26.65 n/a n/a n/a
2026-02-13 2025-12-31 13F COMFORT SYS USA COM Put 1,400 -6.67 1,307 5.58 n/a n/a n/a
2025-11-14 2025-09-30 13F COMFORT SYS USA COM Put 1,500 25.00 1,238 92.38 n/a n/a n/a
2025-08-13 2025-06-30 13F COMFORT SYS USA COM Put 1,200 9.09 643 81.64 n/a n/a n/a
2025-05-14 2025-03-31 13F COMFORT SYS USA COM Put 1,100 355 n/a n/a n/a
2025-02-13 2024-12-31 13F COMFORT SYS USA COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-11-14 2024-09-30 13F COMFORT SYS USA COM Put 900 800.00 351 1,070.00 n/a n/a n/a
2024-08-14 2024-06-30 13F COMFORT SYS USA COM Put 100 30 n/a n/a n/a
2016-11-14 2016-09-30 13F COMFORT SYS USA COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2016-08-15 2016-06-30 13F COMFORT SYS USA COM Put 1,600 300.00 52 333.33 n/a n/a n/a
2016-05-16 2016-03-31 13F COMFORT SYS USA COM Put 400 -91.49 12 -91.04 n/a n/a n/a
2016-02-16 2015-12-31 13F COMFORT SYS USA COM Put 4,700 134 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.