Cash and cash equivalents as of December 31, 2019, 2018, 2017, 2016, and 2015 include cash pledged to secured trust deposits of $384 million, $412 million, $475 million, $331 million, and $108 million, respectively.
As of December 31, 2019, we had cash and cash equivalents of $1,376 million, short term investments of $876 million and available capacity under our Revolving Credit Facility of $800 million. We continually assess our capital allocation strategy, including decisions relating to the amount of our dividend, reducing debt, repurchasing our stock, and/or conserving cash. We believe that all anticipated cash requirements for current operations will be met from internally generated funds, through cash dividends from subsidiaries, cash generated by investment securities, potential sales of non-strategic assets, and borrowings on our Revolving Credit Facility. Our short-term and long-term liquidity requirements are monitored regularly to ensure that we can meet our cash requirements. We forecast the needs of all of our subsidiaries and periodically review their short-term and long-term projected sources and uses of funds, as well as the asset, liability, investment and cash flow assumptions underlying such forecasts.
Short-term investments consist primarily of money market instruments, which are carried at fair value, and commercial paper, which have an original maturity of one year or less and are carried at amortized cost, which approximates fair value.
Our operating lease liability is determined by discounting future lease payments using a discount rate based on the Company's incremental borrowing rate for similar collateralized borrowing. The discount rate is calculated as an average of the current yield on our unsecured notes payable and 140 basis points in excess of the current five year LIBOR swap rate. As of December 31, 2019 the weighted-average discount rate used to determine our operating lease liability was 4.23%.
A summary of the operations of Black Knight included in discontinued operations is shown below:
•Reorganization Agreement, dated as of November 17, 2017, by and between the Company and Cannae, which provides for, among other things, the principal corporate transactions required to effect the Split-Off, certain conditions to the Split-Off and provisions governing the relationship between the Company and Cannae with respect to and resulting from the Split-Off;
At December 31, 2019, we have net operating losses ("NOL") on a pretax basis of $14 million available to carryforward and offset future federal taxable income. The net operating losses are US federal net operating losses arising from acquisitions made since 2012, including Buyers Protection Group, Inc., Digital Insurance Holdings, Inc., and ServiceLink. Most of the NOLs are subject to an annual Internal Revenue Code Section 382 limitation. These losses will begin to expire in year 2023 and we fully anticipate utilizing these losses prior to expiration with the exception of $3 million of gross net operating losses that are offset by a $1 million valuation allowance.
In addition, the Chicago Title Company is also in receipt of a pre-suit demand for approximately $30 million from another group of alleged investors. Chicago Title Company has acknowledged receipt of the claim and is investigating.
We contributed $28 million, $25 million, and $23 million to the ESPP in the years ended December 31, 2019, 2018, and 2017, respectively, in accordance with our matching contribution.