Debt

Secured Debt

On January 5, 2018, we completed a $100,000,000 refinancing of 33-00 Northern Boulevard (Center Building), a 471,000 square foot office building in Long Island City, New York. The seven-year loan is at LIBOR plus 1.80%, which was swapped to a fixed rate of 4.14%. We realized net proceeds of approximately $37,200,000 after repayment of the existing 4.43% $59,800,000 mortgage and closing costs.

On August 9, 2018, we completed a $120,000,000 refinancing of 4 Union Square South, a 206,000 square foot Manhattan retail property. The interest-only loan carries a rate of LIBOR plus 1.40% (3.75% as of December 31, 2018) and matures in 2025, as extended. The property was previously encumbered by a $113,000,000 mortgage at LIBOR plus 2.15%, which was scheduled to mature in 2019.

On November 16, 2018, we completed a $205,000,000 refinancing of 150 West 34th Street, a 78,000 square foot Manhattan retail property. The interest-only loan carries a rate of LIBOR plus 1.88% (4.26% as of December 31, 2018) and matures in 2024, as extended. Concurrently, we invested $105,000,000 in a participation in the refinanced mortgage loan, which earns interest at a rate of LIBOR plus 2.00% (4.38% as of December 31, 2018) and also matures in 2024, as extended, and is included in "other assets" on our consolidated balance sheets. The property was previously encumbered by a mortgage of the same amount at LIBOR plus 2.25%, which was scheduled to mature in 2020.

Unsecured Term Loan

On October 26, 2018, we extended our $750,000,000 unsecured term loan from October 2020 to February 2024. The interest rate on the extended unsecured term loan was lowered from LIBOR plus 1.15% to LIBOR plus 1.00% (3.52% as of December 31, 2018). In connection with the extension of our unsecured term loan, we entered into an interest rate swap from LIBOR plus 1.00% to a fixed rate of 3.87% through October 2023.


11.	Debt – continued

The following is a summary of our debt:



(Amounts in thousands)	Weighted Average Interest Rate at December 31, 2018	Balance at December 31,
	Weighted Average Interest Rate at December 31, 2018	2018			2017
Mortgages Payable:
Fixed rate	3.53%	$	5,003,465		$	5,461,706
Variable rate	4.33%	3,212,382			2,742,133
Total	3.84%	8,215,847			8,203,839
Deferred financing costs, net and other		(48,049		)	(66,700		)
Total, net		$	8,167,798		$	8,137,139
Unsecured Debt:
Senior unsecured notes	4.21%	$	850,000		$	850,000
Deferred financing costs, net and other		(5,998		)	(6,386		)
Senior unsecured notes, net		844,002			843,614

Unsecured term loan	3.87%	750,000			750,000
Deferred financing costs, net and other		(5,179		)	(1,266		)
Unsecured term loan, net		744,821			748,734

Unsecured revolving credit facilities	3.46%	80,000			—

Total, net		$	1,668,823		$	1,592,348

The net carrying amount of properties collateralizing the mortgages payable amounted to $9.1 billion at December 31, 2018.

As of December 31, 2018, the principal repayments required for the next five years and thereafter are as follows:



(Amounts in thousands)	Mortgages Payable		Senior Unsecured Debt and Unsecured Resolving Credit Unsecured Facilities
Year Ended December 31,
2019	$	2,569,332	$	—
2020	2,192,567		—
2021	1,613,948		80,000
2022	950,000		400,000
2023	391,800		—
Thereafter	498,200		1,200,000