<?xml version="1.0" ?>
<informationTable xsi:schemaLocation="http://www.sec.gov/edgar/document/thirteenf/informationtable eis_13FDocument.xsd" xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable" xmlns:n1="http://www.sec.gov/edgar/document/thirteenf/informationtable" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <infoTable>
    <nameOfIssuer>Accenture PLC</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>G1151C101</cusip>
    <value>37332</value>
    <shrsOrPrnAmt>
      <sshPrnamt>300</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>300</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Alibaba Group Holding</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>01609W102</cusip>
    <value>76784</value>
    <shrsOrPrnAmt>
      <sshPrnamt>800</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>800</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>American Express Company</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>025816109</cusip>
    <value>216852075</value>
    <shrsOrPrnAmt>
      <sshPrnamt>641100</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>641100</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>American International Group Inc.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>026874784</cusip>
    <value>223590</value>
    <shrsOrPrnAmt>
      <sshPrnamt>3000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>3000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Bank of New York Mellon Corporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>064058100</cusip>
    <value>36297110</value>
    <shrsOrPrnAmt>
      <sshPrnamt>251000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>251000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Berkshire Hathaway Inc. Class A</nameOfIssuer>
    <titleOfClass>CL A</titleOfClass>
    <cusip>084670108</cusip>
    <value>497985250</value>
    <shrsOrPrnAmt>
      <sshPrnamt>665</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>665</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Berkshire Hathaway Inc. Class B</nameOfIssuer>
    <titleOfClass>CL B</titleOfClass>
    <cusip>084670702</cusip>
    <value>99277376</value>
    <shrsOrPrnAmt>
      <sshPrnamt>198400</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>198400</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Charles Schwab Corporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>808513105</cusip>
    <value>999930</value>
    <shrsOrPrnAmt>
      <sshPrnamt>10837</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>10837</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Ecolab Inc.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>278865100</cusip>
    <value>2713661</value>
    <shrsOrPrnAmt>
      <sshPrnamt>9740</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>9740</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Equity Residential SBI</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>29476L107</cusip>
    <value>81516000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1200000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1200000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Goldman Sachs Group Inc.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>38141G104</cusip>
    <value>82527792</value>
    <shrsOrPrnAmt>
      <sshPrnamt>81600</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>81600</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Infleqtion Inc.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>45676K103</cusip>
    <value>154164055</value>
    <shrsOrPrnAmt>
      <sshPrnamt>11573878</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>11573878</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>JPMorgan Chase &amp; Co.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>46625H100</cusip>
    <value>856801987</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2617548</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2617548</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MasterCard Incorporated</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>57636Q104</cusip>
    <value>3595200</value>
    <shrsOrPrnAmt>
      <sshPrnamt>7000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>7000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Progressive Corporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>743315103</cusip>
    <value>18830390</value>
    <shrsOrPrnAmt>
      <sshPrnamt>86200</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>86200</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Shattuck Labs Inc.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>82024L103</cusip>
    <value>3024098</value>
    <shrsOrPrnAmt>
      <sshPrnamt>435749</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>435749</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>State Street Corporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>857477103</cusip>
    <value>4371101</value>
    <shrsOrPrnAmt>
      <sshPrnamt>25773</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>25773</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>US Bancorp</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>902973304</cusip>
    <value>33824000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>560000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>560000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>W.R. Berkley Corporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>084423102</cusip>
    <value>238039</value>
    <shrsOrPrnAmt>
      <sshPrnamt>3375</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>3375</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Wells Fargo &amp; Co.</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>949746101</cusip>
    <value>20933869</value>
    <shrsOrPrnAmt>
      <sshPrnamt>253314</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>253314</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>Western Alliance Bancorporation</nameOfIssuer>
    <titleOfClass>COM</titleOfClass>
    <cusip>957638109</cusip>
    <value>30877444</value>
    <shrsOrPrnAmt>
      <sshPrnamt>375638</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>375638</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
</informationTable>
