The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
ABB Ltd SPONSORED ADR 000375204 1 49 SH   SOLE   49 0 0
Acuity Brands, Inc. COM 00508Y102 2 15 SH   SOLE   15 0 0
Advanced Energy Industries, Inc. COM 007973100 1 22 SH   SOLE   22 0 0
Albemarle Corporation COM 012653101 5 48 SH   SOLE   48 0 0
Algonquin Power & Utilities COM 015857105 1 114 SH   SOLE   114 0 0
American Water Works Company COM 030420103 11 123 SH   SOLE   123 0 0
Anadarko Petroleum Corp COM 032511107 9,913 147,053 SH   SOLE   147,053 0 0
Andeavor COM 03349M105 2,478 16,144 SH   SOLE   16,144 0 0
Andeavor Logistics, L.P. COM UNIT LP INT 03350F106 715,140 14,726,926 SH   SOLE   13,319,707 0 1,407,219
Antero Midstream GP LP COM SHS REPSTG 03675Y103 112,121 6,626,532 SH   SOLE   6,060,699 0 565,833
Antero Midstream Partners, L.P. UNT LTD PARTN 03673L103 367,166 12,811,090 SH   SOLE   11,380,593 0 1,430,497
Antero Resources Corp COM 03674X106 8,321 469,859 SH   SOLE   469,859 0 0
Apache Corp COM 037411105 2 42 SH   SOLE   42 0 0
Aptiv PLC SHS G6095L109 2 18 SH   SOLE   18 0 0
Aqua America, Inc. COM 03836W103 4 107 SH   SOLE   107 0 0
Aquaventure Holdings Ltd SHS G0443N107 5 277 SH   SOLE   277 0 0
Atlantica Yield PLC SHS G0751N103 38 1,861 SH   SOLE   1,861 0 0
Autoliv, Inc. COM 052800109 1 8 SH   SOLE   8 0 0
Badger Meter, Inc. COM 056525108 3 53 SH   SOLE   53 0 0
Baker Hughes, a GE Company, L.L.C. CL A 05722G100 2 69 SH   SOLE   69 0 0
BorgWarner, Inc. COM 099724106 1 24 SH   SOLE   24 0 0
BP Midstream Partners, L.P. UNIT LTD PTNR 0556EL109 112,966 6,008,834 SH   SOLE   5,206,082 0 802,752
Brookfield Renewable Energy Pa PARTNERSHIP UNIT G16258108 17 564 SH   SOLE   564 0 0
Buckeye Partners, L.P. UNIT LTD PARTN 118230101 419,636 11,790,497 SH   SOLE   10,681,585 0 1,108,912
Cabot Oil & Gas Corp. COM 127097103 17,320 769,103 SH   SOLE   769,103 0 0
Cactus, Inc. CL A 127203107 1 19 SH   SOLE   19 0 0
Carrizo Oil & Gas, Inc. COM 144577103 4,689 186,080 SH   SOLE   186,080 0 0
Celanese Corporation COM 150870103 2 16 SH   SOLE   16 0 0
Centennial Resource Development CL A 15136A102 6,172 282,451 SH   SOLE   282,451 0 0
Chart Industries, Inc. COM PAR $0.01 16115Q308 1 7 SH   SOLE   7 0 0
Cheniere Energy Inc. COM 16411R208 512,013 7,368,147 SH   SOLE   7,131,758 0 236,389
Cheniere Energy Partners, L.P. COM UNIT 16411Q101 606 15,360 SH   SOLE   15,360 0 0
Chevron Corp COM 166764100 2 18 SH   SOLE   18 0 0
Cia Energetica de Minas Gerais SP ADR N-V PFD 204409601 18 10,800 SH   SOLE   10,800 0 0
Cimarex Energy Co COM 171798101 7,604 81,818 SH   SOLE   81,818 0 0
Clearway Energy, Inc. CL C 18539C204 29 1,514 SH   SOLE   1,514 0 0
Cms Energy Corp COM 125896100 163 3,322 SH   SOLE   3,322 0 0
CNX Midstream Partners, L.P. COM UNIT REPST 12654A101 96,250 5,000,000 SH   SOLE   5,000,000 0 0
Concho Resources, Inc. COM 20605P101 16,317 106,821 SH   SOLE   106,821 0 0
Connecticut Water Service, Inc. COM 207797101 1 16 SH   SOLE   16 0 0
ConocoPhillips COM 20825c104 2,932 37,885 SH   SOLE   37,885 0 0
Continental Resources, Inc. COM 212015101 20,081 294,105 SH   SOLE   294,105 0 0
Core Laboratories N.V. COM N22717107 1 10 SH   SOLE   10 0 0
Covanta Holding Corporation COM 22282E102 33 2,000 SH   SOLE   2,000 0 0
Danaher Corporation COM 235851102 6 54 SH   SOLE   54 0 0
DCP Midstream, L.P. COM UT LTD PTN 23311P100 73,182 1,848,487 SH   SOLE   1,848,487 0 0
Delek Logistics Partners, L.P. COM UNT RP INT 24664T103 4,054 119,249 SH   SOLE   119,249 0 0
Delek US Holdings, Inc. COM 24665A103 9,834 231,761 SH   SOLE   231,761 0 0
Delphi Technologies PLC SHS G2709G107 2 54 SH   SOLE   54 0 0
Devon Energy Corporation COM 25179M103 15,510 388,321 SH   SOLE   388,321 0 0
Diamondback Energy, Inc. COM 25278X109 15,028 111,161 SH   SOLE   111,161 0 0
Dominion Energy, Inc. COM 25746U109 212 3,020 SH   SOLE   3,020 0 0
Dominion Energy Midstream Partners COM UT REP LTD 257454108 117,665 6,380,140 SH   SOLE   5,718,780 0 661,360
Dril-Quip, Inc. COM 262037104 1 20 SH   SOLE   20 0 0
DTE Energy Company COM 233331107 4 41 SH   SOLE   41 0 0
DTE Energy Preferred UNIT 99/99/9999 233331883 2,048 39,600 SH   SOLE   39,600 0 0
Duke Energy Corporation COM 26441C204 3 36 SH   SOLE   36 0 0
Eastman Chemical Co COM 277432100 2 17 SH   SOLE   17 0 0
Ecolab, Inc. COM 278865100 5 32 SH   SOLE   32 0 0
Edison International COM 281020107 3 49 SH   SOLE   49 0 0
Enbridge Energy Management, L.L.C. SHS UNITS LLI 29250X103 23,983 2,196,241 SH   SOLE   2,196,241 0 0
Enbridge Energy Partners, L.P. COM 29250R106 114,373 10,406,987 SH   SOLE   10,406,987 0 0
Enbridge, Inc. COM 29250N105 210,736 6,526,348 SH   SOLE   6,526,348 0 0
Energy Recovery, Inc. COM 29270J100 1 72 SH   SOLE   72 0 0
Energy Transfer, L.P. COM UT LTD PTN 29273V100 564,227 32,371,033 SH   SOLE   28,088,297 0 4,282,736
Energy Transfer Partners, L.P. UNIT LTD PRT INT 29278N103 925,323 41,568,861 SH   SOLE   38,671,180 0 2,897,681
Enlink Midstream Partners, L.P. COM UNIT REP LTD 29336U107 264,924 14,212,687 SH   SOLE   13,303,783 0 908,904
Enlink Midstream, L.L.C. COM UNIT REP LTD 29336T100 84,003 5,106,566 SH   SOLE   5,106,566 0 0
Ensco PLC SHS CLASS A G3157S106 0 35 SH   SOLE   35 0 0
Enterprise Products Partners, L.P. COM 293792107 1,214,143 42,260,456 SH   SOLE   37,310,644 0 4,949,812
EOG Resources, Inc. COM 26875P101 24,967 195,711 SH   SOLE   195,711 0 0
EQGP Holdings, L.P. COM UNIT REP 26885J103 11,554 554,702 SH   SOLE   549,639 0 5,063
EQM Midstream Partners, L.P. UNIT LTD PARTN 26885B100 792,584 15,016,757 SH   SOLE   13,463,937 0 1,552,820
EQT Corp COM 26884L109 31,043 701,848 SH   SOLE   701,848 0 0
Esco Technologies, Inc. COM 296315104 2 35 SH   SOLE   35 0 0
ETRACS Alerian MLP Infrastruct ALERIAN INFRST 902641646 77 3,202 SH   SOLE   3,202 0 0
Evoqua Water Technologies Corp COM 30057T105 4 243 SH   SOLE   243 0 0
Extraction Oil & Gas, L.L.C. COM 30227M105 3,923 347,496 SH   SOLE   347,496 0 0
Exxon Mobil Corp COM 30231G102 3 35 SH   SOLE   35 0 0
FireEye, Inc. COM 31816Q101 1 53 SH   SOLE   53 0 0
Ford Motor Co COM PAR $0.01 345370860 2 207 SH   SOLE   207 0 0
Forum Energy Technologies, Inc. COM 34984V100 0 41 SH   SOLE   41 0 0
FTS International Inc. COM 30283W104 1 49 SH   SOLE   49 0 0
GasLog Partners, L.P. UNIT LTD PTNRP Y2687W108 56,250 2,250,000 SH   SOLE   2,250,000 0 0
Genesis Energy, L.P. UNIT LTD PARTN 371927104 1,107 46,539 SH   SOLE   46,539 0 0
Golar LNG Ltd. SHS G9456A100 1 25 SH   SOLE   25 0 0
Gulfport Energy Corp COM 402635304 1 53 SH   SOLE   53 0 0
Halliburton Company COM 406216101 1 34 SH   SOLE   34 0 0
Hannon Armstrong Sustainable I COM 41068X100 43 1,980 SH   SOLE   1,980 0 0
Helmerich & Payne, Inc. COM 423452101 1 20 SH   SOLE   20 0 0
Hess Corp COM 42809H107 1 13 SH   SOLE   13 0 0
Hess Corp DEP PDF SR A 42809H404 4,769 60,000 SH   SOLE   60,000 0 0
Holly Energy Partners, L.P. COM UT LTD PTN 435763107 217,901 6,926,285 SH   SOLE   6,926,285 0 0
HollyFrontier Corporation COM 436106108 1,461 20,897 SH   SOLE   20,897 0 0
IDEX Corporation COM 45167R104 3 20 SH   SOLE   20 0 0
InfraREIT, Inc. COM 45685L100 23 1,080 SH   SOLE   1,080 0 0
Itron, Inc. COM 465741106 6 90 SH   SOLE   90 0 0
Keane Group, Inc. COM 48669A108 1 70 SH   SOLE   70 0 0
Kinder Morgan, Inc COM 49456B101 320,241 18,062,082 SH   SOLE   18,062,082 0 0
Laredo Petroleum, Inc. COM 516806106 2,715 332,276 SH   SOLE   332,276 0 0
Lear Corporation COM 521865204 0 3 SH   SOLE   3 0 0
Liberty Oilfield Services, Inc COM CL A 53115L104 0 16 SH   SOLE   16 0 0
Lindsay Corporation COM 535555106 1 6 SH   SOLE   6 0 0
Magellan Midstream Partners, L.P. COM UNIT RP LP 559080106 1,139,268 16,823,215 SH   SOLE   14,833,864 0 1,989,351
Magna International, Inc. COM 559222401 2 44 SH   SOLE   44 0 0
Marathon Oil Corp COM 565849106 3 115 SH   SOLE   115 0 0
Marathon Petroleum Corp COM 56585A102 2,874 35,942 SH   SOLE   35,942 0 0
Micron Technology, Inc. COM 595112103 2 52 SH   SOLE   52 0 0
MiX Telematics Ltd SPONSORED ADR 60688N102 14 1,000 SH   SOLE   1,000 0 0
Monolithic Power Systems, Inc. COM 609839105 3 23 SH   SOLE   23 0 0
MPLX LP COM UNIT REP LTD 55336V100 977,550 28,187,706 SH   SOLE   24,880,200 0 3,307,506
MRC Global, Inc. COM 55345K103 1 27 SH   SOLE   27 0 0
Mueller Water Products, Inc. COM SER A 624758108 3 288 SH   SOLE   288 0 0
National Fuel Gas Co COM 636180101 21,677 386,681 SH   SOLE   386,681 0 0
NATIONAL OILWELL VARCO, INC. COM 637071101 1 22 SH   SOLE   22 0 0
Newfield Exploration Co COM 651290108 6,042 209,558 SH   SOLE   209,558 0 0
Newpark Resources, Inc. COM PAR $.01 651718504 1 91 SH   SOLE   91 0 0
Nextera Energy, Inc. COM 65339F101 359 2,144 SH   SOLE   2,144 0 0
Nextera Energy Partners, L.P. COM UNIT PART IN 65341B106 359 7,410 SH   SOLE   7,410 0 0
Nio, Inc. SPON ADS 62914V106 1 159 SH   SOLE   159 0 0
Nisource, Inc. COM 65473P105 31,805 1,276,301 SH   SOLE   1,276,301 0 0
Noble Energy, Inc. COM 655044105 2,521 80,828 SH   SOLE   80,828 0 0
Noble Midstream Partners, L.P. COM UNIT REPST 65506L105 92,178 2,603,168 SH   SOLE   2,325,288 0 277,880
NuStar Energy, L.P. UNIT COM 67058H102 81,123 2,918,079 SH   SOLE   2,918,079 0 0
nVent Electric PLC SHS G6700G107 1 23 SH   SOLE   23 0 0
NVIDIA Corporation COM 67066G104 3 9 SH   SOLE   9 0 0
Occidental Petroleum Corp COM 674599105 15,637 190,297 SH   SOLE   190,297 0 0
Oceaneering International, Inc. COM 675232102 1 27 SH   SOLE   27 0 0
Olin Corporation COM PAR $1 680665205 1 42 SH   SOLE   42 0 0
ONEOK, Inc. COM 682680103 997,880 14,720,159 SH   SOLE   13,503,976 0 1,216,183
Ormat Technologies, Inc. COM 686688102 2 32 SH   SOLE   32 0 0
Parsley Energy, Inc. CL A 701877102 8,550 292,313 SH   SOLE   292,313 0 0
Pattern Energy Group, Inc. CL A 70338P100 50 2,492 SH   SOLE   2,492 0 0
Patterson-UTI Energy, Inc. COM 703481101 1 64 SH   SOLE   64 0 0
PBF Logistics, L.P. UNIT LTD PTNR 69318Q104 38,278 1,776,219 SH   SOLE   1,776,219 0 0
PDC Energy, Inc. COM 69327R101 2,865 58,526 SH   SOLE   58,526 0 0
Pembina Pipeline Corp COM 706327103 210,417 6,192,403 SH   SOLE   6,192,403 0 0
Pentair plc SHS G7S00T104 6 129 SH   SOLE   129 0 0
Phillips 66 Partners, L.P. COM UNIT REP INT 718549207 598,428 11,693,897 SH   SOLE   10,443,958 0 1,249,939
Pioneer Natural Resources Co COM 723787107 22,377 128,461 SH   SOLE   128,461 0 0
Plains All American Pipeline, L.P. UNIT LTD PARTN 726503105 905,827 36,218,579 SH   SOLE   31,516,939 0 4,701,640
Plains GP Holdings, L.P. LTD PARTNR INT A 72651A207 229,753 9,366,203 SH   SOLE   9,366,203 0 0
PPL Corporation COM 69351T106 3 96 SH   SOLE   96 0 0
QEP Resources, Inc. COM 74733V100 1 68 SH   SOLE   68 0 0
Range Resources Corp COM 75281A109 7,966 468,860 SH   SOLE   468,860 0 0
Schlumberger, Ltd. COM 806857108 4 66 SH   SOLE   66 0 0
Select Energy Services Inc. CL A COM 81617J301 0 28 SH   SOLE   28 0 0
Semgroup Corp CL A 81663A105 110,710 3,924,251 SH   SOLE   3,924,251 0 0
Sempra Energy COM 816851109 245 2,155 SH   SOLE   2,155 0 0
Sempra Energy 6% PFD CONV A 816851406 5,042 50,000 SH   SOLE   50,000 0 0
Shell Midstream Partners, L.P. UNIT LTD INT 822634101 401,238 18,766,964 SH   SOLE   17,197,698 0 1,569,266
SM Energy Co COM 78454L100 2,780 88,159 SH   SOLE   88,159 0 0
Spectra Energy Partners, L.P. COM 84756N109 103,324 2,893,423 SH   SOLE   2,893,423 0 0
Splunk, Inc. COM 848637104 1 8 SH   SOLE   8 0 0
Sunrun, Inc. COM 86771W105 4 294 SH   SOLE   294 0 0
Superior Energy Services, Inc. COM 868157108 1 74 SH   SOLE   74 0 0
Tallgrass Energy, L.P. CLASS A SHS 874696107 570,676 24,201,701 SH   SOLE   22,216,870 0 1,984,831
Targa Resources Corp. COM 87612G101 492,396 8,744,388 SH   SOLE   8,160,794 0 583,594
TechnipFMC PLC COM G87110105 1 37 SH   SOLE   37 0 0
Terraform Power, Inc. COM CL A 88104R209 38 3,299 SH   SOLE   3,299 0 0
Tesla, Inc. COM 88160R101 8 30 SH   SOLE   30 0 0
Tetra Tech, Inc. COM 88162G103 3 51 SH   SOLE   51 0 0
The Goodyear Tire & Rubber Com COM 382550101 1 41 SH   SOLE   41 0 0
Transcanada Corp COM 89353D107 317,719 7,852,665 SH   SOLE   7,852,665 0 0
Transocean Ltd. REG SHS H8817H100 1 40 SH   SOLE   40 0 0
USA Compression Partners, L.P. COM UNIT LTD PAR 90290N109 1 33 SH   SOLE   33 0 0
Valero Energy Corp COM 91913Y100 13,947 122,614 SH   SOLE   122,614 0 0
Valero Energy Partners, L.P. COM UNT REP LP 91914J102 257,716 6,803,490 SH   SOLE   5,962,685 0 840,805
Veoneer, Inc. COM 92336X109 0 8 SH   SOLE   8 0 0
Verisk Analytics, Inc. COM 92345Y106 1 10 SH   SOLE   10 0 0
Vistra Energy Corp. COM 92840M102 2 63 SH   SOLE   63 0 0
Watts Water Technologies, Inc. CL A 942749102 2 28 SH   SOLE   28 0 0
WEC Energy Group, Inc. COM 92939U106 239 3,584 SH   SOLE   3,584 0 0
Western Gas Equity Partners, L.P. COMUNT LTD PT 95825R103 55,686 1,859,935 SH   SOLE   1,665,727 0 194,208
Western Gas Partners, L.P. COM UNIT LP IN 958254104 711,798 16,295,738 SH   SOLE   14,512,874 0 1,782,864
Westlake Chem Corp COM 960413102 2 21 SH   SOLE   21 0 0
WildHorse Resource Development COM 96812T102 5,986 253,233 SH   SOLE   253,233 0 0
Williams Companies, Inc. COM 969457100 1,138,898 41,886,657 SH   SOLE   37,858,054 0 4,028,603
WPX Energy, Inc. COM 98212B103 15,241 757,516 SH   SOLE   757,516 0 0
Xylem, Inc. COM 98419M100 13 166 SH   SOLE   166 0 0