William Blair & Company
MPLX icon

William Blair & Company’s MPLX MPLX Stock Holding History

William Blair & Company’s Portfolio MPLX Stock Details MPLX Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$2.22M Buy
38,911
+1,767
+5% +$100K 0.01% 704
2025
Q4 		$1.98M Buy
37,144
+2,602
+8% +$136K 0.01% 746
2025
Q3 		$1.73M Buy
34,542
+1,092
+3% +$55.4K ﹤0.01% 769
2025
Q2 		$1.72M Sell
33,450
-37
-0.1% -$1.88K ﹤0.01% 756
2025
Q1 		$1.79M Buy
33,487
+14,967
+81% +$784K 0.01% 739
2024
Q4 		$886K Buy
18,520
+5,965
+48% +$278K ﹤0.01% 938
2024
Q3 		$558K Sell
12,555
-439
-3% -$18.8K ﹤0.01% 1084
2024
Q2 		$553K Buy
12,994
+1,542
+13% +$63.5K ﹤0.01% 1062
2024
Q1 		$476K Buy
11,452
+54
+0.5% +$2.09K ﹤0.01% 1098
2023
Q4 		$419K Buy
11,398
+56
+0.5% +$2.01K ﹤0.01% 1122
2023
Q3 		$403K Sell
11,342
-155
-1% -$5.41K ﹤0.01% 1117
2023
Q2 		$390K Buy
11,497
+2,097
+22% +$71.6K ﹤0.01% 1144
2023
Q1 		$324K Sell
9,400
-13,066
-58% -$449K ﹤0.01% 1212
2022
Q4 		$738K Sell
22,466
-8,083
-26% -$264K ﹤0.01% 928
2022
Q3 		$917K Buy
30,549
+14,003
+85% +$440K ﹤0.01% 842
2022
Q2 		$482K Buy
16,546
+6,467
+64% +$207K ﹤0.01% 1076
2022
Q1 		$334K Sell
10,079
-2,242
-18% -$72.4K ﹤0.01% 1324
2021
Q4 		$365K Sell
12,321
-4,679
-28% -$140K ﹤0.01% 1341
2021
Q3 		$484K Sell
17,000
-1,549
-8% -$43.9K ﹤0.01% 1165
2021
Q2 		$549K Buy
18,549
+4,353
+31% +$123K ﹤0.01% 1120
2021
Q1 		$364K Buy
14,196
+97
+0.7% +$2.38K ﹤0.01% 1259
2020
Q4 		$305K Sell
14,099
-2,609
-16% -$51.5K ﹤0.01% 1259
2020
Q3 		$263K Buy
16,708
+254
+2% +$4.59K ﹤0.01% 1188
2020
Q2 		$284K Sell
16,454
-868
-5% -$14.8K ﹤0.01% 1116
2020
Q1 		$201K Sell
17,322
-3,867
-18% -$79.2K ﹤0.01% 1167
2019
Q4 		$539K Sell
21,189
-256
-1% -$6.52K ﹤0.01% 959
2019
Q3 		$601K Buy
21,445
+12,675
+145% +$371K ﹤0.01% 893
2019
Q2 		$282K Sell
8,770
-1,259
-13% -$40.1K ﹤0.01% 1165
2019
Q1 		$330K Sell
10,029
-3,617
-27% -$121K ﹤0.01% 1112
2018
Q4 		$413K Sell
13,646
-1,180
-8% -$39.4K ﹤0.01% 974
2018
Q3 		$514K Sell
14,826
-9,847
-40% -$353K ﹤0.01% 950
2018
Q2 		$842K Sell
24,673
-35,175
-59% -$1.22M 0.01% 788
2018
Q1 		$1.98M Buy
59,848
+353
+0.6% +$12.7K 0.01% 556
2017
Q4 		$2.11M Sell
59,495
-1,750
-3% -$61.6K 0.01% 560
2017
Q3 		$2.14M Sell
61,245
-4,318
-7% -$149K 0.02% 541
2017
Q2 		$2.19M Buy
65,563
+2,730
+4% +$94.5K 0.02% 548
2017
Q1 		$2.3M Buy
62,833
+505
+0.8% +$18.6K 0.02% 511
2016
Q4 		$2.16M Buy
62,328
+2,735
+5% +$88.8K 0.02% 480
2016
Q3 		$2.02M Hold
59,593
– – 0.02% 496
2016
Q2 		$2M Buy
59,593
+4,999
+9% +$159K 0.02% 479
2016
Q1 		$1.62M Buy
54,594
+436
+0.8% +$11.8K 0.02% 501
2015
Q4 		$2.13M Buy
+54,158
New +$2.04M 0.02% 454

Other funds holding MPLX

AA
ALPS Advisors Denver, Colorado $21.3B AUM 23.41% 1-Year Est. Return
Invesco
Invesco Atlanta, Georgia $1.02T AUM 30.18% 1-Year Est. Return
Blackstone Inc
Blackstone Inc New York $25.6B AUM 26.83% 1-Year Est. Return
TCA
Tortoise Capital Advisors Overland Park, Kansas $9.6B AUM 19.53% 1-Year Est. Return
Goldman Sachs
Goldman Sachs New York $871B AUM 31.28% 1-Year Est. Return
Mirae Asset Global ETFs Holdings
Mirae Asset Global ETFs Holdings Causeway Bay, Hong Kong $73.7B AUM 53.56% 1-Year Est. Return
KACA
Kayne Anderson Capital Advisors Los Angeles, California $5.22B AUM 17.11% 1-Year Est. Return
UBS Group
UBS Group Zurich, Switzerland $666B AUM 30.12% 1-Year Est. Return
CCM
Chickasaw Capital Management Memphis, Tennessee $2.78B AUM 20.87% 1-Year Est. Return
EIP
Energy Income Partners Westport, Connecticut $6.22B AUM 18.97% 1-Year Est. Return

William Blair & Company's MPLX Position: Q1 2026 in Review

William Blair & Company increased its MPLX (MPLX) stake by 4.8% in Q1 2026, buying an estimated $100K and bringing the position to 38,911 shares worth $2.22M. The position accounts for 0.01% of the portfolio, ranked #704.

William Blair & Company first reported a position in MPLX in Q4 2015 and has held it in 42 quarters since. The position peaked at $2.3M in Q1 2017. 644 funds tracked by Wall St. Rank hold MPLX as of Q1 2026.

  • William Blair & Company held 38,911 shares of MPLX worth $2.22M as of Q1 2026.
  • William Blair & Company bought 1,767 MPLX shares in Q1 2026, an estimated $100K.
  • MPLX made up 0.01% of William Blair & Company's portfolio in Q1 2026, its #704 holding.
  • William Blair & Company first reported a position in MPLX in Q4 2015 and has held it in 42 quarters since.
  • William Blair & Company's MPLX position peaked at $2.3M in Q1 2017.
  • 644 funds tracked by Wall St. Rank held MPLX as of Q1 2026.

Based on William Blair & Company's 13F filing for Q1 2026, filed 8 May 2026.