of issue of such obligations) on all marketable inter-
est-bearing obligations of the United States then 
forming a part of the public debt which are not due 
or callable earlier than 4 years after the end of such 
calendar month. Any average market yield computed 
under this paragraph which is not a multiple of one- 
eighth of 1 percent shall be rounded to the nearest 
multiple of one-eighth of 1 percent. 
‘‘(f) FIXED
INCOME
INVESTMENT
ACCOUNT.— 
Amounts in the Fixed Income Investment Account shall 
be invested in instruments or obligations which return the 
amount invested and pay interest, at a specified rate or 
rates, on that amount during a specified period of time, 
consisting of instruments or obligations in one or more 
of the following categories: 
‘‘(1) insurance contracts; 
‘‘(2) certificates of deposit; or 
‘‘(3) other instruments or obligations selected 
by qualified professional asset managers. 
‘‘(g) COMMON
STOCK
INDEX
INVESTMENT
AC-
COUNT.— 
‘‘(1) PORTFOLIO DESIGN.—Amounts held in the 
Common Stock Investment Account shall be invested 
in a portfolio of common stock designed to replicate 
the performance of the index selected under para-
graph (2). The portfolio shall be designed such that, 
to the extent practicable, the percentage of the bal-
ance in the Common Stock Index Investment Ac-
count that is invested in each stock is the same as 
the percentage determined by dividing the aggregate 
market value of all shares of that stock by the ag-
gregate market value of all shares of all stocks in-
cluded in such index. 
‘‘(2) SELECTION OF INDEX.—The Board shall 
select, for purposes of investment of amounts held in 
the Common Stock Investment Account, an index 
which is a commonly recognized index comprised of 
common stock the aggregate market value of which 
is a reasonably complete representation of the 
United States equity markets. 
‘‘(h) SMALL CAPITALIZATION STOCK INDEX INVEST-
MENT ACCOUNT.— 
‘‘(1) PORTFOLIO DESIGN.—Amounts held in the 
Small Capitalization Stock Index Investment Ac-
count shall be invested in a portfolio of common 
stock designed to replicate the performance of the 
index selected under paragraph (2). The portfolio 
shall be designed such that, to the extent prac-
ticable, the percentage of the balance in the Small 
Capitalization Stock Index Investment Account that
is invested in each stock is the same as the percent-
age determined by dividing the aggregate market 
value of all shares of that stock by the aggregate 
market value of all shares of all stocks included in 
such index. 
‘‘(2) SELECTION OF INDEX.—The Board shall 
select, for purposes of investment of amounts held in 
the Small Capitalization Stock Index Investment Ac-
count, an index which is a commonly recognized 
index comprised of common stock the aggregate 
market value of which represents the United States 
equity markets excluding the common stocks in-
cluded in the Common Stock Index Investment Ac-
count. 
‘‘(i) INTERNATIONAL STOCK INDEX INVESTMENT 
ACCOUNT.— 
‘‘(1) PORTFOLIO DESIGN.—Amounts held in the 
International Stock Index Investment Account shall 
be invested in a portfolio of stock designed to rep-
licate the performance of the index selected under 
paragraph (2). The portfolio shall be designed such 
that, to the extent practicable, the percentage of the 
balance in the International Stock Index Investment 
Account that is invested in each stock is the same 
as the percentage determined by dividing the aggre-