13F Pro

SEC Form 4 reporting owner

Bain Capital Life Sciences Investors, LLC

Bain Capital Life Sciences Investors, LLC has filed 9 Form 4 transactions reported between February 4, 2026 and May 20, 2026, as a reporting owner of RAPID MICRO BIOSYSTEMS, INC., a reporting owner of Heartflow, Inc. and a reporting owner of Kailera Therapeutics, Inc..

Name as filed: Bain Capital Life Sciences Investors, LLC

Open-market buys, 24 mo
None
reported
Open-market sales, 24 mo
$115.0M
5 lines
Companies
3
with Form 4 filings
Latest transaction
May 20, 2026
transaction date

Roles and reported holdings

  • RPIDRAPID MICRO BIOSYSTEMS, INC.
    May 20, 2026

    Reporting owner

    Held indirectly (latest line)1,463,000 sh as of May 20, 2026 · Form 4
  • HTFLHeartflow, Inc.
    Feb 4, 2026 – Apr 30, 2026

    Reporting owner

    Held indirectly (latest line)8,448,158 sh as of Apr 30, 2026 · Form 4

    24 months: $115.0M sold

  • KLRAKailera Therapeutics, Inc.
    Apr 20, 2026

    Reporting owner

    No common-stock holding reported on a purchase, sale, gift or withholding line.

    1 line is priced far from KLRA’s market price that day, so the filing may concern a different security. Left out of totals and holdings; see the filings.

Transaction history

All 9 reported transactions, newest first. Every row links to the Form 4 on SEC EDGAR.

DateCompanyTypeSharesValueFiling
May 20, 2026RPIDOpen-market purchaseCode P · indirect1,463,000—Form 4
Apr 30, 2026HTFLOpen-market saleCode S · indirect56,224$1.7M@ $30.05Form 4
Apr 30, 2026HTFLOpen-market saleCode S · indirect892,533$26.0M@ $29.18Form 4
Apr 29, 2026HTFLOpen-market saleCode S · indirect797,133$23.4M@ $29.37Form 4
Apr 28, 2026HTFLOpen-market saleCode S · indirect254,110$7.8M@ $30.51Form 4
Apr 20, 2026KLRAOpen-market purchaseCode P · indirectPrice far from market; may be another securityAlso reported by Koppel Adam1,562,500$25.0M@ $16.00Form 4
Apr 20, 2026KLRAConversion of derivativeCode C · indirect4,145,768—Form 4
Apr 20, 2026KLRAConversion of derivativeCode C · indirect16,875,000—Form 4
Feb 4, 2026HTFLOpen-market saleCode S · indirect2,000,000$56.1M@ $28.05Form 4

How this page is built

Every row comes from a Form 4 filed with the SEC, which officers, directors and holders of more than 10% of a company’s stock must file within two business days of a trade. Transactions are grouped by the reporting owner’s name as filed (spacing, capitals and punctuation ignored); two different people filing under an identical name would appear together, and one person filing under two spellings appears on two pages.

Open-market totals count code P purchases and code S sales over the last 24 months. The same trade reported on more than one filing is counted once; when another owner (for example a fund and its general partner) reports the identical trade, they are listed beside it. Holdings are the shares owned after the latest purchase, sale, gift or tax-withholding line, shown separately for direct and indirect ownership; an indirect figure is one holding line, not a total across every trust or entity.

1 open-market line is priced outside 0.67×–1.5× of the stock’s closing price that day. A gap that large usually means the filing reports a different security than the company it is filed under, so those lines are shown but left out of totals and holdings.

This page describes what was filed with the SEC; it is not investment advice or a recommendation to buy or sell any security.