Security key
83171G103
- Security type / class
- Equity / COM
- Total 13F shares
- 1
- Total 13F value
- $14
- Share change
- +1
- SEC-reported price per share
- $14.00
- Number of holders
- 1
- Value change
- +$14
- Number of buys
- 1
Report period
Q1 2021
Institutions
1
Top holders
1
SPRO full security history
Ownership snapshot
Full 13F holder table
Spero Therapeutics, Inc. SEC filings
Spero Therapeutics, Inc. company facts
Broader feeds
Ownership snapshot
Top reported holders of SPRO - SMARTPROS LTD - COM (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Aquilo Capital Management...
Disclosed value leader
Aquilo Capital Management...
Comparable rows
0/15
Latest evidence
31 Dec 2020
13F
Highest disclosed value: $76,246,000
15 rows are not safely comparable across share classes.
Showing 1-6 of 15 holder rows.
Quick read
Aquilo Capital Management, LLC has the largest disclosed position value at $76.25M.
0 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Aquilo Capital Management, LLC's linked filing trail.
Disclosed position value
Top 5
Aquilo Capital Management, LLC
$76.25M
BVF INC/IL
$43.5M
BlackRock Finance, Inc.
$33.58M
Atlas Venture Associates IX, LLC
$26.7M
Rock Springs Capital Management LP
$23.95M
Value bars compare disclosed positions; verify each figure against the linked filing evidence.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Aquilo Capital Management, LLC |
13F
Company
|
—
denominator unverified
|
$76,246,000
3,932,209 shares
|
— | 31 Dec 2020 |
| BVF INC/IL |
13F
Company
|
—
denominator unverified
|
$43,497,000
2,243,278 shares
|
— | 31 Dec 2020 |
| BlackRock Finance, Inc. |
13F
Company
|
—
denominator unverified
|
$33,576,000
1,731,600 shares
|
— | 31 Dec 2020 |
| Atlas Venture Associates IX, LLC |
13F
Company
|
—
denominator unverified
|
$26,700,000
1,376,968 shares
|
— | 31 Dec 2020 |
| Rock Springs Capital Management LP |
13F
Company
|
—
denominator unverified
|
$23,947,000
1,235,000 shares
|
— | 31 Dec 2020 |
| VANGUARD GROUP INC |
13F
Company
|
—
denominator unverified
|
$21,925,000
1,130,730 shares
|
— | 31 Dec 2020 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q1 2021
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
1
Shares
1
Rows available
1
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q1 2021 vs Q1 2021 Across Filers
Q1 2021 holders
1
Q1 2021 holders
1
Holder diff
0
| Investor | Q1 2021 Shares | Q1 2021 Shares | Share Diff | Share Chg % | Q1 2021 value | Q1 2021 value | Value change | Value Chg % |
|---|