Exhibit 99.1

United States Commodity Index Funds Trust

United States Commodity Index Fund

Monthly Account Statement

For the Month Ended May 31, 2019

Statement of Income (Loss)
Income
Realized Trading Gain (Loss) on Futures	$	(5,105,664	)
Unrealized Gain (Loss) on Market Value of Futures		(14,672,258	)
Dividend Income		27,847
Interest Income		778,799
ETF Transaction Fees		3,500
Total Income (Loss)	$	(18,967,776	)
Expenses
Management Fees	$	266,676
Professional Fees		56,578
Brokerage Commissions		57,616
Non-interested Directors' Fees and Expenses		4,062
Prepaid Insurance Expense		4,937
Total Expenses	$	389,869
Net Income (Loss)	$	(19,357,645	)

Statement of Changes in Net Asset Value
Net Asset Value Beginning of Month 5/1/19	$	413,623,077
Withdrawals (800,000 Shares)		(30,064,833	)
Net Income (Loss)		(19,357,645	)
Net Asset Value End of Month	$	364,200,599
Net Asset Value Per Share (10,000,000 Shares)	$	36.42

To the Shareholders of United States Commodity Index Fund:

Pursuant to Rule 4.22(h) under the Commodity Exchange Act, the undersigned represents that, to the best of his knowledge and belief, the information contained in the Account Statement for the month ended May 31, 2019 is accurate and complete.

/s/ Stuart P. Crumbaugh

Stuart P. Crumbaugh

Chief Financial Officer

United States Commodity Funds LLC, Sponsor of United States Commodity Index Fund

United States Commodity Funds LLC

1850 Mt. Diablo Boulevard, Suite 640

Walnut Creek, CA 94596

United States Commodity Index Funds Trust

United States Copper Index Fund

Monthly Account Statement

For the Month Ended May 31, 2019

Statement of Income (Loss)
Income
Realized Trading Gain (Loss) on Futures	$	(184,700	)
Realized Trading Gain (Loss) on Short-Term Investments		31
Unrealized Gain (Loss) on Market Value of Futures		(1,126,063	)
Dividend Income		1,853
Interest Income		25,534
ETF Transaction Fees		700
Total Income (Loss)	$	(1,282,645	)
Expenses
Management Fees	$	7,403
Professional Fees		8,323
Brokerage Commissions		178
Non-interested Directors' Fees and Expenses		140
Prepaid Insurance Expense		62
Total Expenses		16,106
Expense Waiver		(6,995	)
Net Expenses	$	9,111
Net Income (Loss)	$	(1,291,756	)
Statement of Changes in Net Asset Value
Net Asset Value Beginning of Month 5/1/19	$	14,543,703
Additions (50,000 Shares)		877,151
Withdrawals (150,000 Shares)		(2,577,383	)
Net Income (Loss)		(1,291,756	)
Net Asset Value End of Month	$	11,551,715
Net Asset Value Per Share (700,000 Shares)	$	16.50

To the Shareholders of United States Copper Index Fund:

Pursuant to Rule 4.22(h) under the Commodity Exchange Act, the undersigned represents that, to the best of his knowledge and belief, the information contained in the Account Statement for the month ended May 31, 2019 is accurate and complete.

/s/ Stuart P. Crumbaugh

Stuart P. Crumbaugh

Chief Financial Officer

United States Commodity Funds LLC, Sponsor of United States Copper Index Fund

United States Commodity Funds LLC

1850 Mt. Diablo Boulevard, Suite 640

Walnut Creek, CA 94596

United States Commodity Index Funds Trust

Monthly Account Statement

For the Month Ended May 31, 2019

Statement of Income (Loss)
Income
Realized Trading Gain (Loss) on Futures	$	(5,290,364	)
Realized Trading Gain (Loss) on Short-Term Investments		31
Unrealized Gain (Loss) on Market Value of Futures		(15,798,321	)
Dividend Income		29,700
Interest Income		804,333
ETF Transaction Fees		4,200
Total Income (Loss)	$	(20,250,421	)
Expenses
Management Fees	$	274,079
Professional Fees		64,901
Brokerage Commissions		57,794
Non-interested Directors' Fees and Expenses		4,202
Prepaid Insurance Expense		4,999
Total Expenses		405,975
Expense Waiver		(6,995	)
Net Expenses	$	398,980
Net Income (Loss)	$	(20,649,401	)
Statement of Changes in Net Asset Value
Net Asset Value Beginning of Month 5/1/19	$	428,166,780
Additions (50,000 Shares)		877,151
Withdrawals (950,000 Shares)		(32,642,216	)
Net Income (Loss)		(20,649,401	)
Net Asset Value End of Month	$	375,752,314

To the Shareholders of the Series of the United States Commodity Index Funds Trust:

Pursuant to Rule 4.22(h) under the Commodity Exchange Act, the undersigned represents that, to the best of his knowledge and belief, the information contained in the Account Statement for the month ended May 31, 2019 is accurate and complete.

/s/ Stuart P. Crumbaugh

Stuart P. Crumbaugh

Chief Financial Officer

United States Commodity Funds LLC, Sponsor of United States Commodity Index Funds Trust

United States Commodity Funds LLC

1850 Mt. Diablo Boulevard, Suite 640

Walnut Creek, CA 94596