of 35% due to income generated in jurisdictions other than the United States, principally representing interest income and underwriting income taxed in a jurisdiction with a lower effective tax rate and, for the 2016 period, a $16.3 million favorable settlement of IRS examinations for the 2007 through 2012 tax years. The effective tax rate on non-U.S. income for 2016 and 2015 was 0.6% and 1.3%, respectively.
The $6.4 million unfavorable change in other revenues (expenses) compared to 2014, was driven by a $3.7 million negative adjustment to the pre-tax gain on sale of Essentia. In addition, 2015 net other revenues (expenses) included a $1.6 million pre-tax write-off of certain capitalized software associated with senior management restructuring, as well as an additional loss on the sale of real estate of $1.2 million in 2015. These other expenses were partially offset by the $3.0 million Crop Transaction Fee in 2015.
Net written premiums for Specialty Products increased $7.9 million, or 1.5%, to $540.9 million for 2016 from $533.0 million for 2015, reflecting strong growth at our newer Financial Institutions business ($18.0 million), and across most of our other businesses ($27.4 million), in addition to the adverse impact of the Crop exit on the prior period ($9.5 million). These increases were partially offset by decreases at Programs ($32.3 million), as we have exited two large accounts as a result of poor underwriting results, and Healthcare ($14.7 million), reflecting the impact of refocusing our sales activity on more desirable risks, as well as a large return premium on a single account, and increased competition.
Specialty Industries-Year ended December 31, 2016 versus year ended December 31, 2015
In the fourth quarter of 2014, in conjunction with the Runoff Transaction, we provided financing in the form of surplus notes having a par value of $101.0 million, which had a fair value of $64.9 million on the date of sale. The surplus notes, issued by one of the transferred entities, Bedivere Insurance Company (Bedivere; the Issuer), were in the form of both seller priority and pari passu notes.
Gross investment returns on average invested assets versus typical benchmarks are as follows:
Our common equity securities portfolio returned 2.3% in 2015, outperforming the S&P 500 Index return of 1.4% compared to 8.2% in 2014, underperforming the S&P 500 Index return of 13.7%. Both variances to the S&P 500 Index returns can largely be attributed to the results of our actively-managed publicly-traded common equity securities portfolio.
During 2016, insurance float increased by $22.7 million, primarily from an increase of unrestricted collateral held relating to our Surety business.
Represents anticipated delay in securing regulatory approvals of interest and principal payments to reflect graduated changes in Issuer's statutory surplus. The monetary impact of the anticipated delay is measured based on credit spreads of public securities with roughly equivalent percentages of discounted payments missed. The favorable year-over-year change in impact is driven primarily by the narrowing of non-investment grade credit spreads, which causes the anticipated delay in securing regulatory approval to be less punitive, partially offset by the change in estimates and assumptions regarding the timeline, amounts, and process necessary to obtain regulatory approval for principal and interest payments described below.
Our range of loss and LAE reserve estimates was evaluated to consider the strengths and weaknesses of the various actuarial methods applied against our historical claims experience data. The following table shows the recorded reserves and the high and low ends of our range of reasonable loss and LAE reserves estimates, net of reinsurance recoverable on unpaid losses, as of December 31, 2016 and 2015. The high and low ends of our range of reserve estimates in the table below are based on the results of various actuarial methods described in Note 3-"Unpaid Loss and Loss Adjustment Expense ("LAE") Reserves."
changes in interest rates, debt or equity markets or other market volatility that negatively impact our investment portfolio;