# Boundless Bio, Inc. (BOLD) insider trading

> In the 12 months to Oct 30, 2026, 3 BOLD insiders reported open-market sales of $134.0K across 3 filings; one 10% owner bought $1.9M.

Canonical: https://massive.com/quote/bold/insider-trading
Latest filing: 2026-10-26 (last 12 months; source: SEC EDGAR)
Source: Massive (https://massive.com/docs/llms.txt)

## Summary

| Measure | Value | Detail |
| --- | --- | --- |
| Open-market sales | $134.0K | 3 filings · 3 insiders |
| Open-market purchases | $1.9M | 8 filings · Kevin Tang, 10% owner |

## Open-market trades by insider

| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
| --- | --- | --- | --- | --- | --- | --- |
| Kevin Tang | 10% owner | $54.4K | $1.9M | 9 | — | 2026-10-26 |
| ARCH Venture Partners IX Overage, L.P. | 10% owner | $39.8K | — | 1 | — | 2026-07-06 |
| Robert Nelsen | 10% owner | $39.8K | — | 1 | — | 2026-07-06 |

## Open-market trades by filing

11 filings in the last 12 months, newest first.

| Filed | Traded | Insider | Role | Type | Shares | Avg price | Value | Held after | Filing |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2026-10-26 | 2026-10-22 | Kevin Tang | 10% owner | Purchase | 21,640 | $2.39 | $51.6K | 3,011,749 | — |
| 2026-10-20 | 2026-10-16 | Kevin Tang | 10% owner | Purchase | 149,474 | $2.34 | $349.6K | 2,990,109 | — |
| 2026-08-28 | 2026-08-26 | Kevin Tang | 10% owner | Sale | 18,300 | $2.97 | $54.4K | 2,840,635 | — |
| 2026-07-21 | 2026-07-17 | Kevin Tang | 10% owner | Purchase | 4,863 | $2.44 | $11.9K | 2,858,935 | — |
| 2026-07-16 | 2026-07-14 | Kevin Tang | 10% owner | Purchase | 63,969 | $2.43 | $155.6K | 2,854,072 | — |
| 2026-07-13 | 2026-07-09 | Kevin Tang | 10% owner | Purchase | 91,585 | $2.42 | $222.1K | 2,790,103 | — |
| 2026-07-08 | 2026-07-06 | Kevin Tang | 10% owner | Purchase | 57,210 | $2.48 | $141.9K | 2,698,518 | — |
| 2026-07-06 | 2026-07-01 | ARCH Venture Partners IX Overage, L.P. | 10% owner | Sale | 16,000 | $2.49 | $39.8K | 0 | — |
| 2026-07-06 | 2026-07-01 | Robert Nelsen | 10% owner | Sale | 16,000 | $2.49 | $39.8K | 0 | — |
| 2026-07-02 | 2026-06-30 | Kevin Tang | 10% owner | Purchase | 107,463 | $2.50 | $268.9K | 2,641,308 | — |
| 2026-06-29 | 2026-06-25 | Kevin Tang | 10% owner | Purchase | 286,333 | $2.50 | $714.8K | 2,533,068 | — |

## Other insider activity (not market trades)

- Option exercises: 2 records

Reported on Form 4 but not purchases or sales in the market, so not counted in the totals above.

## How to read this page

- **Open-market purchase or sale**: A buy or sell of the company's stock at market price. Grants, option exercises, shares withheld for tax, gifts and employee stock plan purchases are listed separately and not counted.
- **Filing date**: Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.
- **Counted once**: When several owners (a fund and its partners, say) report the same trade, it's counted once. Corrected filings replace the originals.

## FAQ

### Has Boundless Bio, Inc.'s CEO sold stock?

No. Zachary Hornby (CEO) made no open-market sales filed as CEO in the last 12 months.

### How current is BOLD’s insider data?

These are BOLD Form 4 filings from the last year, refreshed daily. The Massive Form 4 API has the full, continuously updated record.

### What counts as an open-market buy or sell?

Only purchases and sales at the market price. Option exercises, grants, gifts, and shares withheld for taxes are reported on Form 4 but are left out of the buy and sell totals.

## Live data

This page joins two Massive endpoints: Form 4 filings and daily prices. The BOLD Form 4 request:

- `GET https://api.massive.com/stocks/filings/vX/form-4?tickers=BOLD&filing_date.gte=2025-10-30&sort=filing_date.desc&limit=500`

Requests need a Massive API key. API reference for agents: https://massive.com/docs/llms.txt. Connect an AI agent through the Massive MCP server: https://massive.com/docs/ai-tools.

## Related

- [Boundless Bio, Inc. (BOLD) stock price](https://massive.com/quote/bold.md)
- [Recent insider trading](https://massive.com/quote/insider-trading.md)
- [Markets overview](https://massive.com/quote/index.md)

Nothing here is investment advice. Data and content are provided for informational purposes under the Massive Terms of Service: https://massive.com/terms