12.	Commitments and Contingencies

We are a party to a number of pending or threatened lawsuits arising out of, or incident to, our ordinary course of business. We believe that any losses in excess of the amounts accrued therefor as liabilities on our financial statements are unlikely to be significant, but litigation is inherently uncertain and there is the potential for a material adverse effect on our financial statements if one or more matters are resolved in a particular period in an amount materially in excess of what we anticipated.

Our leases generally relate to office space that we occupy, have varying terms and expire at various dates through 2030. The following is a schedule by year of future minimum lease payments for noncancellable operating leases as of December 31, 2017 (dollars in thousands):

2018	$	230,083
2019		207,129
2020		184,872
2021		167,879
2022		135,451
Thereafter		438,121
Total minimum payment required	$	1,363,535

Total minimum payments for noncancellable operating leases were not reduced by the minimum sublease rental income of $12.9 million due in the future under noncancellable subleases.

Substantially all leases require us to pay maintenance costs, insurance and property taxes. The composition of total rental expense under noncancellable operating leases consisted of the following (dollars in thousands):

	Year Ended December 31,
		2017			2016			2015
Minimum rentals	$	276,676		$	252,285		$	236,965
Less sublease rentals		(3,446	)		(4,322	)		(4,673	)
	$	273,230		$	247,963		$	232,292

In January 2008, CBRE MCI, a wholly-owned subsidiary of CBRE Capital Markets, entered into an agreement with Fannie Mae under Fannie Mae’s DUS Program to provide financing for multifamily housing with five or more units. Under the DUS Program, CBRE MCI originates, underwrites, closes and services loans without prior approval by Fannie Mae, and in selected cases, is subject to sharing up to one-third of any losses on loans originated under the DUS Program. CBRE MCI has funded loans subject to such loss sharing arrangements with unpaid principal balances of $19.8 billion at December 31, 2017. CBRE MCI, under its agreement with Fannie Mae, must post cash reserves or other acceptable collateral under formulas established by Fannie Mae to provide for sufficient capital in the event losses occur. As of December 31, 2017 and 2016, CBRE MCI had a $58.0 million and a $45.0 million, respectively, letter of credit under this reserve arrangement, and had recorded a liability of approximately $32.9 million and $28.2 million, respectively, for loan loss under such guarantee obligation. Fannie Mae’s recourse under the DUS Program is limited to the assets of CBRE MCI, which assets totaled approximately $614.5 million (including $370.9 million of warehouse receivables, a substantial majority of which are pledged against warehouse lines of credit and are therefore not available to Fannie Mae) at December 31, 2017.

CBRE Capital Markets participates in Freddie Mac’s Multifamily Small Balance Loan (SBL) Program. Under the SBL program, CBRE Capital Markets has certain repurchase and loss reimbursement obligations. These obligations are for the period from origination of the loan to the securitization date. CBRE Capital Markets must post a cash reserve or other acceptable collateral to provide for sufficient capital in the event the obligations are triggered. As of December 31, 2017, CBRE Capital Markets had posted a $5.0 million letter of credit under this reserve arrangement.

We had outstanding letters of credit totaling $69.4 million as of December 31, 2017, excluding letters of credit for which we have outstanding liabilities already accrued on our consolidated balance sheet related to our subsidiaries’ outstanding reserves for claims under certain insurance programs as well as letters of credit related to operating leases. The CBRE Capital Markets letters of credit totaling $63.0 million as of December 31, 2017 referred to in the preceding paragraphs represented the majority of the $69.4 million outstanding letters of credit as of such date. The remaining letters of credit are primarily executed by us in the ordinary course of business and expire at varying dates through September 2018.

We had guarantees totaling $56.1 million as of December 31, 2017, excluding guarantees related to pension liabilities, consolidated indebtedness and other obligations for which we have outstanding liabilities already accrued on our consolidated balance sheet, and excluding guarantees related to operating leases. The $56.1 million primarily represents guarantees executed by us in the ordinary course of business, including various guarantees of management and vendor contracts in our operations overseas, which expire at the end of each of the respective agreements.

In addition, as of December 31, 2017, we had issued numerous non-recourse carveout, completion and budget guarantees relating to development projects for the benefit of third parties. These guarantees are commonplace in our industry and are made by us in the ordinary course of our Development Services business. Non-recourse carveout guarantees generally require that our project-entity borrower not commit specified improper acts, with us potentially liable for all or a portion of such entity’s indebtedness or other damages suffered by the lender if those acts occur. Completion and budget guarantees generally require us to complete construction of the relevant project within a specified timeframe and/or within a specified budget, with us potentially being liable for costs to complete in excess of such timeframe or budget. However, we generally use “guaranteed maximum price” contracts with reputable, bondable general contractors with respect to projects for which we provide these guarantees. These contracts are intended to pass the risk to such contractors. While there can be no assurance, we do not expect to incur any material losses under these guarantees.

An important part of the strategy for our Global Investment Management business involves investing our capital in certain real estate investments with our clients. These co-investments generally total up to 2.0% of the equity in a particular fund. As of December 31, 2017, we had aggregate commitments of $38.6 million to fund future co-investments.

Additionally, an important part of our Development Services business strategy is to invest in unconsolidated real estate subsidiaries as a principal (in most cases co-investing with our clients). As of December 31, 2017, we had committed to fund $20.8 million of additional capital to these unconsolidated subsidiaries.