What did Guy Spier buy in Q3 2025?

Guy Spier opened 0 new positions and added to 1 existing holding in the Q3 2025 13F.

What did Guy Spier sell in Q3 2025?

Guy Spier exited 0 positions and trimmed 1.

What Guy Spier bought and sold in Q3 2025

In Q3 2025, Guy Spier (Aquamarine Capital) added to 1, trimmed 1. The book stood at $317M across 14 positions, filed Oct 20, 2025.

0New1Added1Trimmed0Exited

Share𝕏 in

Added to (1)

CNRCore Natural Resources Inc+33% shares · 0.3% · $897K

Trimmed (1)

MUMicron Technology Inc-60% shares · 4.2% · $13M

Guy Spier's other filings

Q4 2025 changes Q1 2025 changes

Guy Spier's full portfolio →

Changes vs the prior quarter's 13F, long US equity positions only (no shorts, options, or non-US listings). ADD/TRIM are share- count changes of ±20% or more. Sourced from SEC EDGAR. Not investment advice.