18 Commitments and contingent liabilities

Leasing commitments

As part of its normal business operations, the Group enters into a number of lease agreements. As of 31 December 2018, such agreements, which are operating leases, total the following obligations for the next five years and thereafter:

Minimum rentals for all operating leases (except those with terms of one month or less that were not renewed) for the years ended 31 December 2017 and 2018 were USD 94 million and USD 86 million, respectively. Sublease rental income for the years ended 31 December 2017 and 2018 was USD 2 million and USD 2 million, respectively.

Other commitments

As a participant in limited and other investment partnerships, the Group commits itself to making available certain amounts of investment funding, callable by the partnerships for periods of up to ten years. The total commitments remaining uncalled as of 31 December 2018 were USD 1 954 million.

The Group enters into a number of contracts in the ordinary course of reinsurance and financial services business which, if the Group’s credit rating and/or defined statutory measures decline to certain levels, would require the Group to post collateral or obtain guarantees. The contracts typically provide alternatives for recapture of the associated business.

Legal proceedings

In the normal course of business operations, the Group is involved in various claims, lawsuits and regulatory matters. In the opinion of management, the disposition of these matters is not expected to have a material adverse effect on the Group’s business, consolidated financial position, results of operations or cash flows.