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

Boundless Bio, Inc.

BOLD · Nasdaq · CIK 0001782303 · Healthcare · Biotechnology

INSIDER SIGNAL

51.3 / 100

1 buyers · 22 purchase transaction lines · $1.5M gross purchase

WHY THIS SIGNAL?

Buyer breadthLow
Purchase sizeModerate
RoleModerate
RecencyLow
ConvictionStrong
Score anatomy

Each bar shows the contribution to the current score; the weights and formula stay unchanged.

Cluster+7.0 / 35
Purchase size+18.9 / 25
Role+14.0 / 20
Recency+2.3 / 10
Conviction+9.1 / 10

What is holding the score back?

  • ⚠ Cluster breadth is moderate · 1 insider(s), not 4+
  • ⚠ Role scores low · most senior buyer: TenPercentOwner (CEO, chair and 10% owners score lowest)
  • ⚠ Purchase activity is becoming less recent

Purchase-size comments are relative to the model scale. Average daily volume is a separate market-context diagnostic.

US-v1.2 ranks qualifying equity purchases under the current 180-day rules. The score is a research priority, not a return forecast or probability. Backtests have not shown that a higher US score is followed by better returns.

Insider activity timeline

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

AprMayJunJulAugSepOct
TANG CAPITAL MANAGEMENT LLC; TANG KEVINTenPercentOwner
●●●●●●●●●●●●●●●●●●▼
BYBEE CLINTON; Burow Kristina; CRANDELL KEITH; GILLIS STEVEN; NELSEN ROBERTTenPercentOwner
○▼
ARCH Venture Fund IX Overage, L.P.; ARCH Venture Fund IX, L.P.; ARCH Venture Fund X Overage, L.P.; ARCH Venture Partners IX Overage, L.P.; ARCH Venture Partners IX, L.P.; ARCH Venture Partners IX, LLC; ARCH Venture Partners X Overage, L.P.; ARCH Venture Partners X, LLCTenPercentOwner
○▼
● Purchase▼ Sale○ Other

—

Purchase breadth & concentration

QUALIFYING BUYERS1
PURCHASE CONCENTRATION100%Largest buyer: TANG CAPITAL MANAGEMENT LLC; TANG KEVIN · $1.5M
CLUSTER BUYING · 15D1 insiderPeak activity: 2026-06-25–2026-07-10

Roles in the peak window: TenPercentOwner. Concentration uses priced qualifying P lines only and does not change the saved score.

SIGNAL HISTORY

51.3 / 100

Latest recorded score

↓ -0.1 ptsversus the previous recorded snapshot
  1. 51.5
  2. 51.5
  3. 51.5
  4. 51.4
  5. 51.3

Only scores saved when a full US scoring run completed are shown; gaps are not reconstructed.

Recent Form 4 activity

22Purchases
3Sales
2Other Form 4 lines
9SEC filings · 365 days
BUYING22 qualifying P line(s) · 180 days
SELLING3 sale line(s) · context only
OTHER2 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 provides additional background on recent price performance and risk. It does not affect the Insider Signal.

Price performance

1M
-10.9%
3M
+3.7%
6M
+123.9%
12M
+94.6%

Volatility & liquidity

Volatility
86.8%
Beta
—
Avg daily value
USD 445,939

Valuation

Market cap
USD 57.6M
P/E
—

Fundamentals

Profit margin
—
ROE
-59.0%
Industry
Biotechnology

Market data

Price data up to: 2026-10-11 · Price source: OpenBB/yfinance; volume from price cache (yfinance) · From SEC filings: Market cap, ROE · Fiscal year ended: 2025-12-31 · Market cap is the shares outstanding stated on the filing cover multiplied by the latest close. Share count date: 2026-08-05 · Status: PASS

Short interest

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

Shares short
778,470
Previous report
811,956
Avg daily volume
183,184
Days to cover
4.2

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
2026-07-21TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock2,975USD 2.44USD 7,259SEC filing ↗
2026-07-20TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock1,623USD 2.44USD 3,960SEC filing ↗
2026-07-17TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock265USD 2.44USD 647SEC filing ↗
2026-07-16TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock18,491USD 2.44USD 45,118SEC filing ↗
2026-07-15TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock1,600USD 2.44USD 3,904SEC filing ↗
2026-07-14TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock43,878USD 2.43USD 106,624SEC filing ↗
2026-07-13TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock48,211USD 2.42USD 116,671SEC filing ↗
2026-07-10TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock43,367USD 2.43USD 105,382SEC filing ↗
2026-07-09TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock7USD 2.48USD 17SEC filing ↗
2026-07-08TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock14,338USD 2.46USD 35,271SEC filing ↗
2026-07-07TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock15,810USD 2.48USD 39,209SEC filing ↗
2026-07-06TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock27,062USD 2.49USD 67,384SEC filing ↗
2026-07-02TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock9,821USD 2.49USD 24,454SEC filing ↗
2026-07-01TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock71,612USD 2.49USD 178,314SEC filing ↗
2026-06-30TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock26,030USD 2.54USD 66,112SEC filing ↗

Form 4 evidence

27 transaction lines in the latest 365-day window; 49 in local history.

DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-26TANG CAPITAL MANAGEMENT LLC; TANG KEVINSale (S)Common Stock18,300USD 2.97USD 54,351SEC filing ↗
2026-07-21TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock2,975USD 2.44USD 7,259SEC filing ↗
2026-07-20TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock1,623USD 2.44USD 3,960SEC filing ↗
Show recent Form 4 evidence (23 grouped rows)
DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-26TANG CAPITAL MANAGEMENT LLC; TANG KEVINSale (S)Common Stock18,300USD 2.97USD 54,351SEC filing ↗
2026-07-21TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock2,975USD 2.44USD 7,259SEC filing ↗
2026-07-20TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock1,623USD 2.44USD 3,960SEC filing ↗
2026-07-17TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock265USD 2.44USD 647SEC filing ↗
2026-07-16TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock18,491USD 2.44USD 45,118SEC filing ↗
2026-07-15TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock1,600USD 2.44USD 3,904SEC filing ↗
2026-07-14TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock43,878USD 2.43USD 106,624SEC filing ↗
2026-07-13TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock48,211USD 2.42USD 116,671SEC filing ↗
2026-07-10TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock43,367USD 2.43USD 105,382SEC filing ↗
2026-07-09TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock7USD 2.48USD 17SEC filing ↗
2026-07-08TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock14,338USD 2.46USD 35,271SEC filing ↗
2026-07-07TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock15,810USD 2.48USD 39,209SEC filing ↗
2026-07-06TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock27,062USD 2.49USD 67,384SEC filing ↗
2026-07-02TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock9,821USD 2.49USD 24,454SEC filing ↗
2026-07-01BYBEE CLINTON; Burow Kristina; CRANDELL KEITH; GILLIS STEVEN; NELSEN ROBERTSale (S)Common Stock16,000USD 2.49USD 39,840SEC filing ↗
2026-07-01BYBEE CLINTON; Burow Kristina; CRANDELL KEITH; GILLIS STEVEN; NELSEN ROBERTOption exercise / conversion (M)Common Stock16,000USD 1.03USD 16,480SEC filing ↗
2026-07-01ARCH Venture Fund IX Overage, L.P.; ARCH Venture Fund IX, L.P.; ARCH Venture Fund X Overage, L.P.; ARCH Venture Partners IX Overage, L.P.; ARCH Venture Partners IX, L.P.; ARCH Venture Partners IX, LLC; ARCH Venture Partners X Overage, L.P.; ARCH Venture Partners X, LLCSale (S)Common Stock16,000USD 2.49USD 39,840SEC filing ↗
2026-07-01ARCH Venture Fund IX Overage, L.P.; ARCH Venture Fund IX, L.P.; ARCH Venture Fund X Overage, L.P.; ARCH Venture Partners IX Overage, L.P.; ARCH Venture Partners IX, L.P.; ARCH Venture Partners IX, LLC; ARCH Venture Partners X Overage, L.P.; ARCH Venture Partners X, LLCOption exercise / conversion (M)Common Stock16,000USD 1.03USD 16,480SEC filing ↗
2026-07-01TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock71,612USD 2.49USD 178,314SEC filing ↗
2026-06-30TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock26,030USD 2.54USD 66,112SEC filing ↗
2026-06-29TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock64,762USD 2.47USD 159,970SEC filing ↗
2026-06-26TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock75,181USD 2.55USD 191,710SEC filing ↗
2026-06-25TANG CAPITAL MANAGEMENT LLC; TANG KEVINPurchase (P)Common Stock146,390USD 2.48USD 363,088SEC 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 · —
TickerBOLD
CIK0001782303
SectorHealthcare
IndustryBiotechnology Yahoo Finance
SEC SIC2834 Pharmaceutical Preparations
ExchangeNasdaq

Data coverage

Local Form 4 history49 transaction lines from 2024-04-02 to 2026-08-26
30 P purchase lines · 3 S sale lines · 16 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.