Short-Term Borrowings

Our short-term borrowings include securities sold under repurchase agreements, federal funds purchased and other short-term borrowings; other short-term borrowings include borrowings associated with our tax-exempt investment program, more fully described in Note 14.

Collectively, short-term borrowings had weighted-average interest rates of 0.25% and 0.13% in 2017 and 2016, respectively.

The following tables present information with respect to the amounts outstanding and weighted-average interest rates of the primary components of our short-term borrowings as of and for the years ended December 31:



	Securities Sold Under Repurchase Agreements									Federal Funds Purchased									Tax-Exempt Investment Program
(Dollars in millions)	2017			2016			2015			2017			2016			2015			2017			2016			2015
Balance as of December 31	$	2,842		$	4,400		$	4,499		$	—		$	—		$	6		$	1,078		$	1,158		$	1,748
Maximum outstanding as of any month-end	4,302			5,572			10,977			—			29			29			1,158			1,726			1,865
Average outstanding during the year	3,683			4,113			8,875			1			31			21			1,127			1,512			1,807
Weighted-average interest rate as of year-end	.03		%	.04		%	.02		%	.00		%	.00		%	.03		%	1.45		%	.67		%	.03		%
Weighted-average interest rate during the year	.05			.02			.01			.00			.17			.01			.79			.36			.06

Obligations to repurchase securities sold are recorded as a liability in our consolidated statement of condition. U.S. government securities with a fair value of $2.90 billion underlying the repurchase agreements remained in our investment securities portfolio as of December 31, 2017.

The following table presents information about these U.S. government securities and the carrying value of the related repurchase agreements, including accrued interest, as of December 31, 2017. The table excludes repurchase agreements collateralized by securities purchased under resale agreements and collateralized by trading account assets.



	U.S. Government Securities Sold				Repurchase Agreements⁽¹⁾
(In millions)	Amortized Cost		Fair Value		Amortized Cost
Overnight maturity	$	2,928	$	2,899	$	2,842

⁽¹⁾ Collateralized by investment securities.

We maintain an agreement with a clearing organization that enables us to net all securities purchased under resale agreements and sold under repurchase agreements with counterparties that are also members of the clearing organization. As a result of this netting, the average balances of securities purchased under resale agreements and securities sold under repurchase agreements were reduced by $31.15 billion in 2017 compared to $30.86 billion in 2016.

State Street Bank currently maintains a line of credit of CAD 1.40 billion, or approximately $1.11 billion as of December 31, 2017, to support its Canadian securities processing operations. The line of credit has no stated termination date and is cancelable by either party with prior notice. As of December 31, 2017 and 2016, there was no balance outstanding on this line of credit.