Aquamarine Capital Q4 2025 13F Holdings and Activity Report

I. Institutional Overview

The psychological portrait of the institution this quarter is one of extreme discipline and perhaps a cautious outlook on the broader market. The reduction in the number of stocks to just seven indicates a rigorous "weeding of the garden." For a value investor like Spier, who often speaks about the "Education of a Value Investor" and the importance of avoiding the "noise" of Wall Street from his base in Zurich, this report reflects a return to core principles. The institution is no longer interested in "peripheral" bets or "cloned" positions that do not meet the highest thresholds of certainty and long-term durability. By exiting long-standing positions like Bank of America (BAC) and Micron Technology (MU) , Spier is signaling that the "harvest season" has arrived for many of his multi-year bets.

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II. Sector Allocation Analysis

The concentration in Financials is not just a sector preference; it is a fundamental macro judgment. By holding nearly 90% of the portfolio in companies like Berkshire Hathaway , American Express , Mastercard , and Moody’s , Spier is betting on the continued dominance of the American-led financial system and the "toll-taking" nature of these businesses. These are companies that do not just participate in the economy; they provide the rails upon which the economy runs. The sum of the top three sectors is 100%, indicating a total lack of diversification in the traditional sense. This "highly focused" approach suggests that Spier views the current macro environment as one where only the strongest "moats" are worth defending.

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III. Top 10 Holdings Deep Dive

Combined, the two share classes of Berkshire Hathaway represent 48.6% of the total portfolio. This is the definition of a "conviction holding." Despite a 30.58% reduction in the B shares, the relative weight of Berkshire in the portfolio actually increased significantly because of the total liquidation of other large positions like Bank of America.

The logic is clear: Quality over Quantity. Spier has stripped away everything that isn't a "world-class" compounder. The portfolio market cap style is exclusively Mega-Cap and Large-Cap , with the exception of Daily Journal. The risk-return characteristic is one of "low frequency, high impact." By holding only the "best of the best," Spier is betting that these seven companies will outperform through sheer business-model superiority, regardless of short-term market fluctuations.

This section shows only part of the complete report. View the app for the full analysis, position-level detail, and quarter-over-quarter tracking.

IV. Major Buys/Additions

While Spier reduced his Class B shares, he did not touch a single share of BRK.A . In the context of a massive portfolio liquidation, "doing nothing" with BRK.A is an offensive move. It signals that Spier views the Class A shares as the ultimate "store of value." By allowing the weight of BRK.A to nearly double from 7.13% to 15.35%, he is effectively "adding" to his commitment to the Buffett-led conglomerate.

By not adding anything new, Spier has dramatically lowered the "active risk" of picking a new loser. He is sticking with the "winners" he has known for a decade. This move has increased the portfolio’s concentration risk but decreased its "complexity risk." The institution is now a pure play on a few world-class businesses. The "timing" judgment here is clear: It is a time to harvest, not to sow.

This section shows only part of the complete report. View the app for the full analysis, position-level detail, and quarter-over-quarter tracking.

V. Major Sells and Exits

The overall quality of these exits is high. Spier is selling his winners (BAC, MU, AXP, RACE) to lock in massive gains and selling his losers (BABA, SRG, AMR) to simplify his life. This is "active profit-taking" combined with "strategic pruning." The impact on the portfolio is a massive increase in "quality density." The remaining seven stocks are, in Spier’s view, "unbreakable."

The scale of the cash-out is enormous relative to the fund size. By liquidating nearly $40M in BAC and another $50M+ in AXP reductions, Spier has moved a huge portion of his AUM into a "liquid" or "non-equity" state. This is a "Sell A, Buy Nothing" strategy. It reveals a risk signal: the institution considers the current market to be "fully valued" or "risky," and prefers the safety of Berkshire’s balance sheet and cash over the individual risks of banks, tech, and retail.

This section shows only part of the complete report. View the app for the full analysis, position-level detail, and quarter-over-quarter tracking.

VI. Investment Insights and Risk Warnings

The overarching theme of Guy Spier’s Q4 2025 activity is "The Great Retrenchment: Returning to the Berkshire Core." This is not a fund that is "trading" the market; it is a fund that is "curating" a legacy.

Disclaimer : This analysis is for informational purposes only and does not constitute investment advice. The "smart money" can be wrong, and individual investors should conduct their own due diligence based on their unique risk profiles and financial goals.

This section shows only part of the complete report. View the app for the full analysis, position-level detail, and quarter-over-quarter tracking.

Sources and limitations

This report uses public U.S. Securities and Exchange Commission Form 13F disclosures and structured data maintained by 13F Hub. A 13F filing is a quarter-end snapshot of reportable long positions, is normally published with a delay, and does not disclose every short position, cash balance, bond, derivative, or non-U.S. asset.

Narrative content is prepared from the same-period SEC disclosure and 13F Hub structured data, then checked before publication. This material is for research and education, not personalized investment advice.