ARCH Venture Fund X, L.P. and affiliated entities filed a Form 3 initial statement of beneficial ownership with the SEC on October 29, 2026, disclosing holdings of multiple series of convertible preferred stock in Aspen Neuroscience, Inc. (NASDAQ:ASPE).

Key Highlights

  • Multiple reporting persons: The filing covers nine reporting persons, including ARCH Venture Fund X, L.P., ARCH Venture Fund X Overage, L.P., three ARCH Venture Partners entities, and four individual investment committee members: Keith Crandell, Kristina Burow, Steven Gillis, and Robert Nelsen.
  • Series Seed preferred: ARCH Venture Fund X, L.P. disclosed beneficial ownership of convertible preferred stock underlying 187,182 shares of common stock.
  • Series A-1 preferred: Combined holdings across ARCH X and ARCH X Overage represent 298,258 shares of underlying common stock each, for a total of 596,516 shares on an as-converted basis.
  • Series A-2 preferred: Each of ARCH X and ARCH X Overage disclosed 286,304 underlying common shares, totaling 572,608 on an as-converted basis.
  • Series B preferred: Each of ARCH X and ARCH X Overage disclosed 295,490 underlying common shares, totaling 590,980 on an as-converted basis.
  • Series C preferred: ARCH X disclosed 259,948 underlying common shares and ARCH X Overage disclosed 214,355 underlying common shares.
  • Automatic IPO conversion: According to the filing, each share of preferred stock "will automatically convert on a 1-for-9.8821 basis into shares of Common Stock" upon completion of the issuer's initial public offering, for no additional consideration.

ARCH Venture Fund X Discloses Convertible Preferred Stakes Ahead of Aspen Neuroscience IPO Conversion

The Form 3, filed on October 29, 2026, represents the initial beneficial ownership statement for ARCH Venture Fund X, L.P. and its affiliated entities in Aspen Neuroscience, Inc. According to the filing, all nine reporting persons are identified as 10% owners and directors of the issuer. All reporting persons share the same address: 8755 W. Higgins Road, Suite 1025, Chicago, Illinois 60631.

The filing discloses ownership across five classes of derivative securities: Series Seed, Series A-1, Series A-2, Series B, and Series C Convertible Preferred Stock. The filing states that share numbers "give effect to" the 1-for-9.8821 conversion ratio that will apply automatically upon the completion of the issuer's initial public offering. All positions are held directly, and the securities are reported to carry no expiration date. Holdings are split between two funds: ARCH Venture Fund X, L.P. and ARCH Venture Fund X Overage, L.P., with the former holding Series Seed, A-1, A-2, B, and C preferred, and the latter holding A-1, A-2, B, and C preferred.

The filing notes that ARCH Venture Partners X, LLC serves as the sole general partner of both AVP X LP and AVP X Overage LP, which are themselves the respective general partners of the two funds. The filing states that each of AVP X LP, AVP X Overage LP, AVP X LLC, and the four individual committee members "disclaims beneficial ownership except to the extent of any pecuniary interest therein." All signatures were executed by Mark McDonnell as attorney-in-fact.

What Was Disclosed

ARCH Venture Fund X, L.P. and eight affiliated entities and individuals filed an initial beneficial ownership statement for multiple classes of convertible preferred stock in Aspen Neuroscience, Inc., with share counts reflecting an automatic 1-for-9.8821 IPO conversion ratio.