Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO) Institutional Ownership

13F Institutional Holders and Ownership History from Q4 2017 to Q4 2025

Type / Class
Equity / Common Stock, par value $0.001 per share
Symbol
SPRO on Nasdaq
Shares outstanding
55,705,828
Price per share
$2.33
All holders as of 30 Sep 2025
Q3 2025
Total 13F shares
11,311,502
Total reported value
$21,264,964
% of total 13F portfolios
0%
Share change
+217,023
Value change
-$925,483
Number of holders
47
Price from insider filings
$2.33
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Significant Owners of Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO) based on Schedule 13D/G filings

Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
GSK plc 16% $6,709,142 9,190,606 GSK PLC 27 Mar 2025
Anson Funds Management LP 2.9% $4,587,932 1,615,469 Anson Funds Management LP 30 Jun 2025

As of 30 Sep 2025, 47 institutional investors reported holding 11,311,502 shares of Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO). This represents 20% of the company’s total 55,705,828 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO) together control 20% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
Pfizer Inc 4.2% 2,362,348 0% 1% $4,441,214
VANGUARD GROUP INC 3.6% 1,989,855 +2% 0% $3,740,928
Anson Funds Management LP 2.9% 1,603,569 -0.74% 0.33% $3,014,710
RENAISSANCE TECHNOLOGIES LLC 2.6% 1,452,765 +75% 0% $2,731,198
Alphabet Inc. 1.6% 889,979 0% 0.07% $1,673,161
GEODE CAPITAL MANAGEMENT, LLC 0.95% 527,477 +3.3% 0% $991,889
BlackRock, Inc. 0.78% 434,768 0% 0% $817,363
Informed Momentum Co LLC 0.51% 282,445 +18% 0.06% $530,997
Ionic Capital Management LLC 0.37% 208,725 +39% 0.44% $392,403
STATE STREET CORP 0.34% 190,951 +24% 0% $358,988
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.27% 150,516 0% $282,970
NORTHERN TRUST CORP 0.23% 129,643 +29% 0% $243,729
ADAR1 Capital Management, LLC 0.21% 115,539 -20% 0.02% $217,213
BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.21% 114,800 0% 0% $215,824
INTREPID FAMILY OFFICE LLC 0.2% 110,000 0.19% $206,800
GSA CAPITAL PARTNERS LLP 0.19% 106,894 0.02% $201,000
Shay Capital LLC 0.11% 63,667 0.02% $119,694
TWO SIGMA INVESTMENTS, LP 0.09% 49,399 0% $92,870
MORGAN STANLEY 0.08% 43,378 +370% 0% $81,550
JANE STREET GROUP, LLC 0.08% 42,988 0% $80,818
Cubist Systematic Strategies, LLC 0.07% 40,845 +50% 0% $76,789
AMERICAN CENTURY COMPANIES INC 0.07% 40,219 0% $75,612
Assenagon Asset Management S.A. 0.07% 36,993 0% $69,547
XTX Topco Ltd 0.06% 33,801 -2.2% 0% $63,546
Capital Asset Advisory Services LLC 0.06% 32,548 0% 0% $61,190

Institutional Holders of Spero Therapeutics, Inc. - Common Stock, par value $0.001 per share (SPRO) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2025 Q4 86,484 $207,017 -$42,772 $2.33 4
2025 Q3 11,311,502 $21,264,964 -$925,483 $1.88 47
2025 Q2 11,078,704 $32,127,617 -$7,947,299 $2.90 44
2025 Q1 15,108,016 $10,875,927 -$477,165 $0.72 38
2024 Q4 15,679,985 $16,148,583 +$400,519 $1.03 50
2024 Q3 12,343,754 $16,539,251 -$2,018,983 $1.34 46
2024 Q2 13,876,978 $18,039,320 +$23,111 $1.30 47
2024 Q1 13,757,012 $23,665,168 -$10,720 $1.72 54
2023 Q4 13,365,697 $19,647,483 +$254,060 $1.47 46
2023 Q3 14,186,051 $17,161,812 -$230,667 $1.21 53
2023 Q2 14,363,122 $20,824,354 +$224,803 $1.45 56
2023 Q1 14,249,435 $20,599,780 -$6,707 $1.45 46
2022 Q4 14,222,474 $24,601,496 -$11,539,486 $1.73 57
2022 Q3 19,852,133 $39,711,772 +$134,944 $2.00 61
2022 Q2 20,944,051 $15,519,733 -$13,723,970 $0.74 60
2022 Q1 20,241,451 $176,086,818 +$3,320,960 $8.70 96
2021 Q4 19,791,141 $316,661,728 +$1,752,850 $16.01 82
2021 Q3 18,370,536 $338,246,936 +$16,477,961 $18.41 87
2021 Q2 16,107,401 $224,862,846 -$15,083,084 $13.96 82
2021 Q1 18,548,675 $273,055,350 +$11,246,827 $14.72 89
2020 Q4 19,088,635 $370,127,115 +$23,864,503 $19.39 87
2020 Q3 16,774,007 $187,077,092 +$55,385,284 $11.16 77
2020 Q2 11,755,382 $159,039,554 +$6,802,405 $13.53 76
2020 Q1 11,530,942 $93,166,538 +$5,358,513 $8.08 60
2019 Q4 10,816,370 $103,998,595 +$4,177,290 $9.61 61
2019 Q3 10,374,836 $109,974,592 -$2,905,980 $10.60 59
2019 Q2 10,642,327 $122,390,354 +$15,770,919 $11.51 60
2019 Q1 9,265,285 $118,611,567 +$3,622,037 $12.81 53
2018 Q4 9,098,891 $56,002,988 -$16,910,081 $6.15 50
2018 Q3 10,749,538 $112,996,000 +$24,528,130 $10.51 51
2018 Q2 8,120,919 $119,131,433 +$30,467 $14.67 42
2018 Q1 7,704,769 $109,789,119 -$578,036 $14.25 34
2017 Q4 7,758,590 $91,157,605 +$91,039,605 $11.75 36