Berkshire bought $41.8 billion of stock in nine months as banks fell to 25.6% of holdings

Berkshire Hathaway (NYSE: BRK.A, BRK.B) held $335.5 billion of equity securities at September 30, up 12.7% from $297.8 billion at the end of 2025, and five holdings made up 65% of that value, according to the notes to its third-quarter Form 10-Q. Banks, insurance and finance fell to 25.6% of the portfolio from 35.0% (computed).

The portfolio grew by $37.7 billion, and $23.1 billion of it was cost

The 10-Q table of equity investments, which groups holdings into three categories, shows fair value rising from $297,778 million on December 31, 2025 to $335,515 million on September 30, 2026, an increase of $37.7 billion (computed). The cost basis, what Berkshire paid for the holdings still owned, rose to $108,462 million from $85,389 million, an increase of $23.1 billion (computed). Net unrealized gains rose to $227,053 million from $212,389 million, an increase of $14.7 billion (computed).

The cash flow statement shows how the cost rose. Berkshire's purchases of equity securities were $41,771 million in the first nine months of 2026, against $13,447 million in the same period of 2025, and its sales were $30,572 million, against $24,046 million. Purchases exceeded sales by $11.2 billion (computed); the other part of the cost change is not itemized in these tables.

Banks gave up the most, the broad third category gained the most

The three categories moved in different directions between December 31 and September 30:

Category	Fair value, Dec. 31, 2025	Fair value, Sept. 30, 2026	Change
Banks, insurance and finance	$104.1 billion	$85.9 billion	down 17.5%
Consumer products	$95.0 billion	$112.5 billion	up 18.4%
Commercial, industrial and other	$98.7 billion	$137.2 billion	up 39.0%

Source: Berkshire Hathaway Form 10-Q for the third quarter of 2026, Note 4. Changes computed.

The cost basis tells a similar story. For commercial, industrial and other, it rose to $84,451 million from $58,036 million, which is $26.4 billion more (computed) and more than the whole increase in the portfolio's cost. The cost basis of banks, insurance and finance was $15,357 million, against $15,454 million, almost unchanged, so the 17.5% drop in that category's fair value came from lower market prices or sales, not from new money.

Consumer products went the other way: its cost basis fell to $8,654 million from $11,899 million, while its fair value rose. The 10-Q does not itemize the sales or price gains behind that.

Five holdings, 65% of the value, and a changed list

Berkshire says in the 10-Q that its equity investments "over the years have been concentrated in relatively few companies." The five largest holdings accounted for 65% of the fair value of its equity securities at September 30 and at December 31. The largest five at September 30 were Alphabet Inc., American Express Company, Apple Inc., Bank of America Corporation and The Coca-Cola Company.

The share was not constant in between. The first-quarter report put it at 61% at March 31, and the second-quarter report at 66% at June 30. The list also changed: at March 31 the five included Chevron Corporation and not Alphabet, while the June and September lists include Alphabet and not Chevron.

What the filing does not show

The 10-Q names the five largest holdings but not their order or individual values, and it does not say which holdings Berkshire bought or sold in the period. The sector shift can therefore not be tied to a single company. Nor does the filing give a reason for the changes: the report describes the portfolio and its results, not Berkshire's intent.

Gains and losses on these holdings also feed straight into earnings. Berkshire reported investment gains of $20,851 million in the first nine months of 2026, against $17,243 million a year earlier, and says that changes in the market prices of its equity investments usually produce significant volatility in its earnings. Taxable gains on equity securities sold were $11.8 billion in the nine months, against $18.7 billion in 2025.

A concentrated book is a risk and a choice

We think Berkshire's filings are a useful case study for any investor weighing concentration against diversification. The company holds five names for two-thirds of a $335.5 billion portfolio, and its own filing calls the portfolio concentrated. That is a choice with a visible cost: when one sector, such as banks, falls 17.5% in fair value in nine months, the whole book feels it, while the faster growth of another category cushions the result.

The opportunity for any concentrated holder is that conviction in a few businesses can compound without the drag of a broad portfolio's average holdings. The threat is that a few holdings fall together, and the nine-month record shows both effects at once: banks down, the broad third category up 39.0%. We would weigh how much of a portfolio's result rests on its largest five holdings, and how much those five depend on the same drivers, before reading any one year's gain as skill. If the 65% share keeps rising in the next quarterly reports while the cash pile shrinks, we would read that as a sign of intensifying concentration; if it falls, as diversification. This is a general reading of one company's filing, not a view on any security.

The view in this final section is FinanceInTime's editorial opinion, for information only. It is not investment, tax, legal or other advice, and it does not take your circumstances into account. Forecasts are uncertain and past results do not guarantee future ones.