Energy Recovery, Inc.
US ˙ NasdaqGS ˙ US29270J1007

SecurityERII / Energy Recovery, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership13,081 shares
Latest Disclosed Value $ 131,725
Citigroup Inc ownership in ERII / Energy Recovery, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 13,081 shares of Energy Recovery, Inc. (US:ERII) valued at $131,726 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 24,254 shares of Energy Recovery, Inc.. This represents a change in shares of -46.07% during the quarter. The current value of the position is $105,171 USD.

Citigroup Inc has a history of taking positions in derivatives of the underlying security (ERII) in the form of stock options.

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.

ERII / Energy Recovery, 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)
2026-05-11 2026-03-31 13F ENERGY RECOVERY COM 29270J100 13,081 -11,173 -46.07 132 -59.94 0.0000
2026-02-13 2025-12-31 13F ENERGY RECOVERY COM 29270J100 24,254 18,523 323.21 327 271.59 0.0001
2025-11-10 2025-09-30 13F ENERGY RECOVERY COM 29270J100 5,731 -16,699 -74.45 88 -69.23 0.0000
2025-08-11 2025-06-30 13F ENERGY RECOVERY COM 29270J100 22,430 -25,064 -52.77 287 -62.07 0.0001
2025-05-12 2025-03-31 13F ENERGY RECOVERY COM 29270J100 47,494 -1,053 -2.17 755 5.75 0.0004
2025-02-12 2024-12-31 13F ENERGY RECOVERY COM 29270J100 48,547 7,400 17.98 714 -0.28 0.0004
2024-11-12 2024-09-30 13F ENERGY RECOVERY COM 29270J100 41,147 28,588 227.63 716 330.72 0.0004
2024-08-12 2024-06-30 13F ENERGY RECOVERY COM 29270J100 12,559 3,273 35.25 167 13.70 0.0001
2024-05-10 2024-03-31 13F ENERGY RECOVERY COM 29270J100 9,286 -11,321 -54.94 147 -62.37 0.0001
2024-02-09 2023-12-31 13F ENERGY RECOVERY COM 29270J100 20,607 20,280 6,201.83 388 6,366.67 0.0003
2023-12-06 2023-09-30 13F/A-1 ENERGY RECOVERY COM 29270J100 327 -17,741 -98.19 7 -98.81 0.0000
2023-11-09 2023-09-30 13F ENERGY RECOVERY COM 29270J100 327 -17,741 7 0.0000
2023-08-10 2023-06-30 13F ENERGY RECOVERY COM 29270J100 18,068 11,287 166.45 505 223.72 0.0003
2023-05-11 2023-03-31 13F ENERGY RECOVERY COM 29270J100 6,781 5,125 309.48 156 372.73 0.0001
2023-02-09 2022-12-31 13F ENERGY RECOVERY COM 29270J100 1,656 -2,509 -60.24 34 -63.33 0.0000
2022-11-10 2022-09-30 13F ENERGY RECOVERY COM 29270J100 4,165 -3,123 -42.85 90 -36.17 0.0001
2022-08-10 2022-06-30 13F ENERGY RECOVERY COM 29270J100 7,288 4,400 152.35 141 138.98 0.0001
2022-05-12 2022-03-31 13F ENERGY RECOVERY COM 29270J100 2,888 -10,744 -78.81 59 -79.86 0.0000
2022-02-10 2021-12-31 13F ENERGY RECOVERY COM 29270J100 13,632 3,610 36.02 293 53.40 0.0002
2021-11-10 2021-09-30 13F ENERGY RECOVERY COM 29270J100 10,022 4,873 94.64 191 63.25 0.0001
2021-08-10 2021-06-30 13F ENERGY RECOVERY COM 29270J100 5,149 -380 -6.87 117 15.84 0.0001
2021-05-13 2021-03-31 13F ENERGY RECOVERY COM 29270J100 5,529 -8,519 -60.64 101 -47.40 0.0001
2021-02-11 2020-12-31 13F ENERGY RECOVERY COM 29270J100 14,048 9,232 191.69 192 392.31 0.0001
2020-11-12 2020-09-30 13F ENERGY RECOVERY COM 29270J100 4,816 -9,628 -66.66 39 -64.55 0.0000
2020-08-12 2020-06-30 13F ENERGY RECOVERY COM 29270J100 14,444 614 4.44 110 6.80 0.0001
2020-05-12 2020-03-31 13F ENERGY RECOVERY COM 29270J100 13,830 3,722 36.82 103 4.04 0.0001
2020-02-12 2019-12-31 13F ENERGY RECOVERY COM 29270J100 10,108 1,630 19.23 99 26.92 0.0001
2019-11-08 2019-09-30 13F ENERGY RECOVERY COM 29270J100 8,478 -8,532 -50.16 78 -56.18 0.0001
2019-08-12 2019-06-30 13F ENERGY RECOVERY COM 29270J100 17,010 615 3.75 178 24.48 0.0001
2019-05-13 2019-03-31 13F ENERGY RECOVERY COM 29270J100 16,395 5,695 53.22 143 98.61 0.0001
2019-02-12 2018-12-31 13F ENERGY RECOVERY COM 29270J100 10,700 -18 -0.17 72 -25.00 0.0001
2018-11-13 2018-09-30 13F ENERGY RECOVERY COM 29270J100 10,718 8,718 435.90 96 500.00 0.0001
2018-08-10 2018-06-30 13F ENERGY RECOVERY COM 29270J100 2,000 -1,186 -37.23 16 -38.46 0.0000
2018-05-11 2018-03-31 13F ENERGY RECOVERY COM 29270J100 3,186 -94,996 -96.76 26 -96.97 0.0000
2018-02-12 2017-12-31 13F ENERGY RECOVERY COM 29270J100 98,182 95,070 3,054.95 859 3,336.00 0.0007
2017-11-13 2017-09-30 13F ENERGY RECOVERY COM 29270J100 3,112 -2,457 -44.12 25 -45.65 0.0000
2017-08-11 2017-06-30 13F ENERGY RECOVERY COM 29270J100 5,569 -3,565 -39.03 46 -39.47 0.0000
2017-05-12 2017-03-31 13F ENERGY RECOVERY COM 29270J100 9,134 -35,104 -79.35 76 -83.41 0.0001
2017-02-10 2016-12-31 13F ENERGY RECOVERY COM 29270J100 44,238 36,023 438.50 458 246.97 0.0004
2016-11-10 2016-09-30 13F ENERGY RECOVERY COM 29270J100 8,215 -313 -3.67 132 73.68 0.0001
2016-08-12 2016-06-30 13F ENERGY RECOVERY COM 29270J100 8,528 2,683 45.90 76 26.67 0.0001
2016-05-13 2016-03-31 13F ENERGY RECOVERY COM 29270J100 5,845 -5,504 -48.50 60 -25.00 0.0001
2016-02-12 2015-12-31 13F ENERGY RECOVERY COM 29270J100 11,349 -2,996 -20.89 80 158.06 0.0001
2015-11-13 2015-09-30 13F ENERGY RECOVERY COM 29270J100 14,345 -129 -0.89 31 -20.51 0.0000
2015-08-13 2015-06-30 13F ENERGY RECOVERY COM 29270J100 14,474 8,654 148.69 39 160.00 0.0000
2015-05-14 2015-03-31 13F ENERGY RECOVERY COM 29270J100 5,820 -4,527 -43.75 15 -72.73 0.0000
2015-02-17 2014-12-31 13F ENERGY RECOVERY COM 29270J100 10,347 4,179 67.75 55 150.00 0.0000
2014-11-14 2014-09-30 13F ENERGY RECOVERY COM 29270J100 6,168 2,333 60.83 22 15.79 0.0000
2014-08-14 2014-06-30 13F ENERGY RECOVERY COM 29270J100 3,835 -6,456 -62.73 19 -65.45 0.0000
2014-05-15 2014-03-31 13F ENERGY RECOVERY COM 29270J100 10,291 -9,548 -48.13 55 -50.00 0.0001
2014-02-14 2013-12-31 13F ENERGY RECOVERY COM 29270J100 19,839 10,752 118.32 110 66.67 0.0001
2013-11-14 2013-09-30 13F ENERGY RECOVERY COM 29270J100 9,087 -11,310 -55.45 66 -21.43 0.0001
2013-08-14 2013-06-30 13F ENERGY RECOVERY COM 29270J100 20,397 20,397 84 0.0001
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
(%)
2018-05-11 2018-03-31 13F ENERGY RECOVERY COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-02-12 2017-12-31 13F ENERGY RECOVERY COM Put 100,000 875 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.