Stock Trading Canary

United States · SEC Form 4 · Snapshot date: 2026-10-18 · Built: 2026-10-18 · 中文

← United States · Coverage record

US · SEC FORM 4

Spero Therapeutics, Inc.

SPRO · Nasdaq · CIK 0001701108 · Healthcare · Biotechnology

INSIDER SIGNAL

No active buy signal

0 qualifying P purchase groups
in the current 180-day scoring window

9 Form 4 transaction lines observed in the same window
1 sales · 8 option, withholding, award, gift or other lines

Last qualifying purchase2022-04-26 · Aquilo Capital Management, LLC; Aquilo Capital, L.P. · $208.2K

WHY NO ACTIVE SIGNAL?

Purchase activityNone
Recent buyingNone
Recent salesLow
Buy signal statusInactive
Score anatomy

No score is calculated because there is no qualifying purchase in the active window. Unavailable inputs are not treated as zero or as a bearish signal.

ClusterNot calculated
Purchase sizeNot calculated
RoleNot calculated
RecencyNot calculated
ConvictionNot calculated

Why is there no score?

  • No qualifying open-market purchase supplies cluster, size, role, recency or conviction inputs.
  • Sales and other Form 4 activity remain visible as context and do not create a negative score.

Sales and other Form 4 activity are shown separately and do not create a negative buy signal. Absence of buying is not scored as bearish.

Insider activity timeline

Owner lanes show the latest 180 days. Symbol shape identifies the transaction type; sales remain context only.

AprMayJunJulAugSepOct
Deshpande MilindDirector
○
Tregoning KathleenDirector
○
Smith CynthiaDirector
○
VINK PATRICK V.J.J.Director
○
THOMAS FRANK EDirector
○
Jackson Scott ThomasDirector
○
● Purchase▼ Sale○ Other

Showing the six most active owners; 3 additional owner(s) remain in Form 4 evidence.

Purchase breadth, concentration & cluster buying

These modules activate when qualifying purchases enter the 180-day research window.

SIGNAL HISTORY

No recorded active-signal snapshot

Scores are archived only when the company qualifies for a published US buy-signal snapshot. Last qualifying purchase: 2022-04-26 · Aquilo Capital Management, LLC; Aquilo Capital, L.P..

Recent Form 4 activity

0Purchases
9Sales
10Other Form 4 lines
14SEC filings · 365 days
BUYING0 qualifying P line(s) · 180 days
SELLING1 sale line(s) · context only
OTHER8 exercise / withholding / award / gift / other lines
10b5-1 / PLANNEDNot assessed

P is an open-market or private purchase. S is a sale. M, F, A and G usually describe exercises, tax withholding, awards and gifts. These categories remain visually separate.

Market context

Market context has not been captured for this ticker yet. The daily market-context job processes the US universe in rotating batches.

Short interest

Short interest is external context reported to FINRA by broker-dealers. It does not affect the Insider Signal.

Shares short
794,509
Previous report
976,488
Avg daily volume
1,144,097
Days to cover
≤ 1.0

FINRA settlement date: 2026-09-30 · Captured 2026-10-12 · FINRA equity short interest ↗. A share count, published about a week after each of two settlement dates a month; not a percentage of shares outstanding.

Historical equity purchases

Qualifying code P transactions in the local Form 4 history, including purchases outside the current signal window.

Transaction dateReporting ownerTypeSecuritySharesAvg. priceApprox. valueSource
2022-04-26Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value39,727USD 5.24USD 208,169SEC filing ↗
2022-03-30Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value50,000USD 8.79USD 439,500SEC filing ↗
2022-03-14Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value23,708USD 7.63USD 180,892SEC filing ↗
2022-02-28Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value44,833USD 9.53USD 427,258SEC filing ↗
2022-02-18Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value14,828USD 9.24USD 137,011SEC filing ↗
2022-01-31Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value125,000USD 11.59USD 1,448,750SEC filing ↗
2022-01-24Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value1,599USD 10.89USD 17,413SEC filing ↗
2022-01-18Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value48,488USD 12.41USD 601,736SEC filing ↗
2022-01-10Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value8,867USD 12.93USD 114,650SEC filing ↗
2021-12-31Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value125,000USD 15.75USD 1,968,750SEC filing ↗
2021-12-30Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value50,000USD 15.77USD 788,500SEC filing ↗
2021-12-29Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value75,493USD 14.64USD 1,105,218SEC filing ↗
2021-10-29Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value150,000USD 17.53USD 2,629,500SEC filing ↗
2021-09-30Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value134,543USD 18.65USD 2,509,227SEC filing ↗
2021-09-14Aquilo Capital Management, LLC; Aquilo Capital, L.P.Purchase (P)Common Stock, $0.001 par value2,156USD 18.49USD 39,864SEC filing ↗

Form 4 evidence

19 transaction lines in the latest 365-day window; 184 in local history.

DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-03Zack DebraAward / grant (A)Common Stock162,311USD 0.00USD 0SEC filing ↗
2026-06-23VINK PATRICK V.J.J.Award / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Tregoning KathleenAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
Show recent Form 4 evidence (18 grouped rows)
DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-03Zack DebraAward / grant (A)Common Stock162,311USD 0.00USD 0SEC filing ↗
2026-06-23VINK PATRICK V.J.J.Award / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Tregoning KathleenAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23THOMAS FRANK EAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Smith CynthiaAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Pottage John C JrAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Jackson Scott ThomasAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-06-23Deshpande MilindAward / grant (A)Common Stock10,000USD 0.00USD 0SEC filing ↗
2026-05-04Rajavelu EstherSale (S)Common Stock25,240USD 2.51USD 63,352SEC filing ↗
2026-02-06Rajavelu EstherSale (S)Common Stock87,917USD 2.36USD 207,484SEC filing ↗
2026-02-06Keutzer TimothySale (S)Common Stock18,652USD 2.36USD 44,019SEC filing ↗
2026-02-04Keutzer TimothySale (S)Common Stock3,471USD 2.24USD 7,775SEC filing ↗
2026-02-03Keutzer TimothySale (S)Common Stock24,224USD 2.14USD 51,839SEC filing ↗
2026-02-02Keutzer TimothySale (S)Common Stock18,891USD 2.20USD 41,560SEC filing ↗
2026-02-02Keutzer TimothyAward / grant (A)Common Stock68,000USD 0.00USD 0SEC filing ↗
2026-02-02Rajavelu EstherSale (S)Common Stock18,442USD 2.20USD 40,572SEC filing ↗
2026-02-02Rajavelu EstherAward / grant (A)Common Stock249,000USD 0.00USD 0SEC filing ↗
2025-11-07Rajavelu EstherSale (S)Common Stock40,270USD 2.37USD 95,440SEC filing ↗

Multiple price lines in one filing are grouped and share-weighted. Price and value are blank when a grouped filing line lacks price evidence.

Snapshot & identity

Snapshot date2026-10-18
Ranking versionUS-v1.2
Data qualityPASS ELIGIBLE · —
TickerSPRO
CIK0001701108
SectorHealthcare
IndustryBiotechnology Yahoo Finance
SEC SIC2834 Pharmaceutical Preparations
ExchangeNasdaq

Data coverage

Local Form 4 history184 transaction lines from 2020-06-22 to 2026-08-03
27 P purchase lines · 71 S sale lines · 86 other lines
SEC company submissionsOpen SEC filings ↗

Local ledger as of 2026-10-18. Mapping status is an audit field and does not erase SEC filing evidence.