Oppenheimer Developing Markets Fund (ODVBX) N-CSRS Certified semi-annual shareholder report (management investment company)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORMN-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT

INVESTMENT COMPANIES

Investment Company Act file number811-07657

Oppenheimer Developing Markets Fund

(Exact name of registrant as specified in charter)

6803 South Tucson Way, Centennial, Colorado 80112-3924

(Address of principal executive offices) (Zip code)

Cynthia Lo Bessette

OFI Global Asset Management, Inc.

225 Liberty Street, New York, New York 10281-1008

(Name and address of agent for service)

Registrant’s telephone number, including area code:(303)768-3200

Date of fiscal year end:August 31

Date of reporting period:2/28/2019

Item 1. Reports to Stockholders.

Important Updates

On October 18, 2018, Massachusetts Mutual Life Insurance Company, an indirect corporate parent of OppenheimerFunds, Inc. and its subsidiaries OFI Global Asset Management, Inc., OFI SteelPath, Inc. and OFI Advisors, LLC, announced that it has entered into an agreement whereby Invesco Ltd., a global investment management company, will acquire OppenheimerFunds, Inc. As of the date of this report, the transaction is expected to close in the second quarter of 2019, pending necessary regulatory and other third-party approvals. This is subject to change. See the Notes to Financial Statements for more information.

Update to Shareholder Report Document Delivery

Beginning January 1, 2021, OppenheimerFunds will send a notice, either by mail or email, each time your fund’s updated report is available on our website (oppenheimerfunds.com). Investors who are not enrolled in electronic delivery by January 1, 2021 will receive the notice in the mail. Enrolling in electronic delivery will enable you to receive a direct link to your full shareholder report the moment it becomes available, and limit the amount of mail you receive. All investors who prefer to receive shareholder reports in paper may, at any time, choose that option.

How do you update your delivery preferences?

If you own these shares through a financial intermediary, you may contact your financial intermediary.

If your accounts are held through OppenheimerFunds and you receive statements, confirms, and other documents directly from us, you can enroll in our eDocs Direct^SM service atoppenheimerfunds.com or by calling us. Once you’re enrolled, you’ll begin to receive email notifications of updated documents when they become available. If you have any questions, feel free to call us at1.800.225.5677.

Table of Contents

Top Holdings and Allocations	4
Fund Expenses	7
Consolidated Statement of Investments	9
Consolidated Statement of Assets and Liabilities	15
Consolidated Statement of Operations	17
Consolidated Statements of Changes in Net Assets	19
Consolidated Financial Highlights	20
Notes to Consolidated Financial Statements	30
Board Approval of the Fund’s Investment Advisory andSub-Advisory Agreements	46
Portfolio Proxy Voting Policies and Guidelines; Updates to Statement of Investments	49
Trustees and Officers	50
Privacy Notice	51

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 2/28/19

	Class A Shares of the Fund
		Without Sales Charge	With Sales Charge	MSCI Emerging   Markets Index
6-Month		0.84%	-4.96%	0.33%
1-Year		-5.44	-10.88	-9.89
5-Year		3.53	2.31	4.13
10-Year		12.50	11.84	10.32

Performance data quoted represents past performance, which does not guarantee future results.The investment return and principal value of an investment in the Fund will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Fund returns include changes in share price, reinvested distributions, and a 5.75% maximum applicable sales charge except where “without sales charge” is indicated. Current performance may be lower or higher than the performance quoted. Returns do not consider capital gains or income taxes on an individual’s investment. Returns for periods of less than one year are cumulative and not annualized. For performance data current to the most recentmonth-end, visit oppenheimerfunds.com or call 1.800.CALL OPP (225.5677). See Fund prospectuses and summary prospectuses for more information on share classes and sales charges.

3       OPPENHEIMER DEVELOPING MARKETS FUND

Top Holdings and Allocations

TOP TEN COMMON STOCK HOLDINGS

Alibaba Group Holding Ltd., Sponsored ADR	6.7	%
Taiwan Semiconductor Manufacturing Co. Ltd.	4.9
Kering SA	4.0
Novatek PJSC, Sponsored GDR	3.9
Glencore plc	3.6
Tencent Holdings Ltd.	3.6
Housing Development Finance Corp. Ltd.	3.2
AIA Group Ltd.	3.1
Kotak Mahindra Bank Ltd.	2.8
Jiangsu Hengrui Medicine Co. Ltd., Cl. A	2.3

Portfolio holdings and allocations are subject to change. Percentages are as of February 28, 2019, and are based on net assets.

TOP TEN GEOGRAPHICAL HOLDINGS

China	23.5	%
India	10.2
Russia	7.4
Hong Kong	6.5
Mexico	6.1
France	6.0
Brazil	5.0
Taiwan	4.9
South Korea	4.6
United States	4.6

Portfolio holdings and allocations are subject to change. Percentages are as of February 28, 2019, and are based on total market value of investments.

REGIONAL ALLOCATION

Portfolio holdings and allocations are subject to change. Percentages are as of February 28, 2019, and are based on the total market value of investments.

For more current Fund holdings, please visit oppenheimerfunds.com.

4       OPPENHEIMER DEVELOPING MARKETS FUND

Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 2/28/19

	Inception Date	6-Month	1-Year	5-Year	10-Year
Class A (ODMAX)	11/18/96	0.84%	-5.44%	3.53%	12.50%
Class C (ODVCX)	11/18/96	0.48	-6.14	2.76	11.69
Class I (ODVIX)	12/29/11	1.06	-5.05	3.98	6.34
Class R (ODVNX)	3/1/01	0.72	-5.69	3.27	12.16
Class Y (ODVYX)	9/7/05	0.98	-5.19	3.79	12.83
AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 2/28/19
	Inception Date	6-Month	1-Year	5-Year	10-Year
Class A (ODMAX)	11/18/96	-4.96%	-10.88%	2.31%	11.84%
Class C (ODVCX)	11/18/96	-0.52	-7.08	2.76	11.69
Class I (ODVIX)	12/29/11	1.06	-5.05	3.98	6.34
Class R (ODVNX)	3/1/01	0.72	-5.69	3.27	12.16
Class Y (ODVYX)	9/7/05	0.98	-5.19	3.79	12.83

*Shows performance since inception.

Performance data quoted represents past performance, which does not guarantee future results.The investment return and principal value of an investment in the Fund will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance quoted. Returns do not consider capital gains or income taxes on an individual’s investment. For performance data current to the most recentmonth-end, visit oppenheimerfunds.com or call 1.800. CALL OPP (225.5677). Fund returns include changes in share price, reinvested distributions, and the applicable sales charge: for Class A shares, the current maximum initial sales charge of 5.75% and for Class C shares, the contingent deferred sales charge of 1% for the1-year period. There is no sales charge for Class I, Class R and Class Y shares. Returns for periods of less than one year are cumulative and not annualized. See Fund prospectuses and summary prospectuses for more information on share classes and sales charges.

The Fund’s performance is compared to the performance of the MSCI Emerging Markets Index, which is designed to measure equity market performance of emerging markets. The Index isunmanaged and cannot be purchased directly by investors. While index comparisons may be useful to provide a benchmark for the Fund’s performance, it must be noted that the Fund’s investments are not limited to the investments comprising theIndex. Index performance includes reinvestment of income, but does not reflect transaction costs, fees, expenses or taxes. Index performance is shown for illustrative purposes only as a benchmark for the Fund’s performance, and does not predict or depict performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

Before investing in any of the Oppenheimer funds, investors should carefully consider a fund’s investment objectives, risks, charges and expenses. Fund prospectuses and summary prospectuses contain this and other information about the funds, and may be obtained by

5       OPPENHEIMER DEVELOPING MARKETS FUND

asking your financial advisor, visiting oppenheimerfunds.com, or calling 1.800.CALL OPP (225.5677). Read prospectuses and summary prospectuses carefully before investing.

Shares of Oppenheimer funds are not deposits or obligations of any bank, are not guaranteed by any bank, are not insured by the FDIC or any other agency, and involve investment risks, including the possible loss of the principal amount invested.

6       OPPENHEIMER DEVELOPING MARKETS FUND

Fund Expenses

Fund Expenses. As a shareholder of the Fund, you incur two types of costs: (1) transaction costs, which may include sales charges (loads) on purchase payments and/or contingent deferred sales charges on redemptions; and (2) ongoing costs, including management fees; distribution and service fees; and other Fund expenses. These examples are intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The examples are based on an investment of $1,000.00 invested at the beginning of the period and held for the entire6-month period ended February 28, 2019.

Actual Expenses. The first section of the table provides information about actual account values and actual expenses. You may use the information in this section for the class of shares you hold, together with the amount you invested, to estimate the expense that you paid over the period. Simply divide your account value by $1,000.00 (for example, an $8,600.00 account value divided by $1,000.00 = 8.60), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During 6 Months Ended February 28, 2019” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes.The second section of the table provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio for each class of shares, and an assumed rate of return of 5% per year for each class before expenses, which is not the Fund’s actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example for the class of shares you hold with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such asfront-end or contingent deferred sales charges (loads). Therefore, the “hypothetical” section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

7       OPPENHEIMER DEVELOPING MARKETS FUND

Actual	Beginning Account Value September 1, 2018	Ending Account Value February 28, 2019	Expenses Paid During 6 Months Ended February 28, 2019
Class A	$    1,000.00	$    1,008.40	$          6.39
Class C	1,000.00	1,004.80	10.19
Class I	1,000.00	1,010.60	4.35
Class R	1,000.00	1,007.20	7.64
Class Y	1,000.00	1,009.80	5.15
Hypothetical (5% return before expenses)
Class A	1,000.00	1,018.45	6.43
Class C	1,000.00	1,014.68	10.24
Class I	1,000.00	1,020.48	4.37
Class R	1,000.00	1,017.21	7.68
Class Y	1,000.00	1,019.69	5.17

Expenses are equal to the Fund’s annualized expense ratio for that class, multiplied by the average account value over the period, multiplied by 181/365 (to reflect theone-half year period). Those annualized expense ratios, excluding indirect expenses from affiliated funds, based on the6-month period ended February 28, 2019 are as follows:

Class	Expense Ratios
Class A		1.28%
Class C		2.04
Class I		0.87
Class R		1.53
Class Y		1.03

The expense ratios reflect voluntary and/or contractual waivers and/or reimbursements of expenses by the Fund’s Manager. Some of these undertakings may be modified or terminated at any time, as indicated in the Fund’s prospectus. The “Consolidated Financial Highlights” tables in the Fund’s financial statements, included in this report, also show the gross expense ratios, without such waivers or reimbursements and reduction to custodian expenses, if applicable.

8       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED

STATEMENT OF INVESTMENTSFebruary 28, 2019 Unaudited

	Shares		Value
Common Stocks—94.6%
Consumer Discretionary—31.3%
Entertainment—0.0%
Tencent Music Entertainment Group, Sponsored ADR1		8,537	$	153,837
Hotels, Restaurants & Leisure—4.3%
Alsea SAB de CV2		63,950,859		161,888,735
Huazhu Group Ltd., ADR2		25,122,746		881,054,702
Jollibee Foods Corp.		40,013,873		238,222,905
Yum China Holdings, Inc.		10,123,930		422,370,360
				1,703,536,702
Household Durables—0.0%
Steinhoff International Holdings NV1		115,822,130		16,930,268
Interactive Media & Services—5.4%
NAVER Corp.		1,834,726		217,782,929
Tencent Holdings Ltd.		33,298,110		1,420,871,299
Yandex NV, Cl. A1,2		15,433,830		530,923,752
				2,169,577,980
Internet & Catalog Retail—10.9%
Alibaba Group Holding Ltd., Sponsored ADR1		14,725,681		2,695,241,393
Meituan Dianping, Cl. B1		56,068,000		433,873,251
Meituan Dianping, Cl. B1		48,578,600		357,121,839
MercadoLibre, Inc.1		1,197,330		549,323,031
Pinduoduo, Inc., ADR1		10,360,540		310,194,568
				4,345,754,082
Media—1.1%
Zee Entertainment Enterprises Ltd.2		68,644,603		450,752,956
Multiline Retail—2.1%
Lojas Americanas SA2		87,184,600		462,134,203
SACI Falabella		45,373,578		352,846,030
				814,980,233
Textiles, Apparel & Luxury Goods—7.5%
Kering SA		2,895,148		1,585,356,755

	Shares		Value
Textiles, Apparel & Luxury Goods (Continued)
LVMH Moet Hennessy Louis Vuitton SE		2,287,209	$	787,606,953
Moncler SpA		5,816,186		222,878,619
PRADA SpA		119,610,010		383,511,450
				2,979,353,777
Consumer Staples—7.7%
Beverages—2.5%
Anadolu Efes Biracilik Ve Malt Sanayii AS2		38,338,430		144,098,727
Fomento Economico Mexicano SAB de CV		64,688,597		586,751,415
Fomento Economico Mexicano SAB de CV, Sponsored ADR		3,093,745		280,386,109
				1,011,236,251
Food & Staples Retailing—2.7%
Atacadao Distribuicao Comercio e Industria Ltda		90,774,600		471,738,400
BIM Birlesik Magazalar AS		6,620,645		106,287,505
Shoprite Holdings Ltd.		23,957,240		291,863,990
Wal-Mart de Mexico SAB de CV		76,945,903		198,935,413
				1,068,825,308
Food Products—0.3%
Vietnam Dairy Products JSC		20,419,300		124,456,192
Personal Products—2.2%
Amorepacific Corp.		1,449,666		258,996,938
AMOREPACIFIC Group		1,262,847		82,598,256
LG Household & Health Care Ltd.		478,290		530,411,869
				872,007,063
Energy—4.9%
Oil, Gas & Consumable Fuels—4.9%
LUKOIL PJSC, Sponsored ADR		4,562,041		379,222,103
Novatek PJSC, Sponsored GDR		9,054,718		1,567,418,870
				1,946,640,973

9       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED

STATEMENT OF INVESTMENTSUnaudited / Continued

	Shares		Value
Financials—24.1%
Capital Markets—3.8%
B3SA-Brasil Bolsa Balcao		67,014,248	$	585,013,163
China International Capital Corp. Ltd., Cl. H3		85,576,800		198,453,839
Hong Kong Exchanges & Clearing Ltd.		20,859,782		722,582,973
				1,506,049,975
Commercial Banks—9.9%
Akbank TAS		155,047,553		199,536,681
Banco de Chile		407,535,368		64,694,861
Banco Santander Mexico SA Institucion de Banca Multiple Grupo Financiero Santander, Cl. B		124,563,486		171,003,946
Bandhan Bank Ltd.3		6,849,773		46,301,583
Bank Central Asia Tbk PT		112,323,800		220,526,067
BDO Unibank, Inc.		16,059,900		39,628,291
Commercial International Bank Egypt SAE		45,861,035		183,810,819
Credicorp Ltd.		2,100,012		510,491,917
Grupo Aval Acciones y Valores SA, ADR2		27,098,977		209,475,092
Grupo Financiero Inbursa SAB de CV, Cl. O		207,029,544		308,803,805
Itau Unibanco Holding SA, ADR		20,632,810		193,948,414
Kotak Mahindra Bank Ltd.		66,052,253		1,126,671,528
Sberbank of Russia PJSC		116,701,872		367,812,791
Siam Commercial Bank PCL (The)		43,316,800		184,225,959
Turkiye Garanti Bankasi AS		86,055,036		143,794,487
				3,970,726,241
Consumer Finance—0.3%
Cholamandalam Investment & Finance Co. Ltd.		6,924,201		119,991,373

	Shares		Value
Diversified Financial Services—1.9%
Ayala Corp.		7,523,000	$	134,636,554
FirstRand Ltd.		136,752,054		623,904,715
				758,541,269
Insurance—3.1%
AIA Group Ltd.		122,390,600		1,224,867,834
Real Estate Management & Development—1.9%
Ayala Land, Inc.		311,907,400		265,509,401
Emaar Properties PJSC		126,330,811		168,491,836
Oberoi Realty Ltd.		7,426,580		51,771,205
SM Prime Holdings, Inc.		358,516,972		266,111,517
				751,883,959
Thrifts & Mortgage Finance—3.2%
Housing Development Finance Corp. Ltd.		49,941,105		1,292,668,224
Health Care—6.9%
Biotechnology—0.8%
Biocon Ltd.		25,864,456		226,128,961
Innovent Biologics, Inc.1,3		15,050,500		45,564,817
Shanghai Junshi Biosciences Co. Ltd., Cl. H1,2,3		14,994,000		42,022,740
				313,716,518
Health Care Providers & Services—1.6%
Apollo Hospitals Enterprise Ltd.2		1,078,029		17,310,911
Sinopharm Group Co. Ltd., Cl. H2		142,027,200		634,432,965
				651,743,876
Health Care Technology—0.0%
Ping An Healthcare & Technology Co. Ltd.1,3		2,664,621		13,383,676
Life Sciences Tools & Services—1.5%
Samsung Biologics Co. Ltd.1,3		1,007,226		336,761,115
Wuxi Biologics Cayman, Inc.1,3		25,472,500		240,997,121
				577,758,236
Pharmaceuticals—3.0%
Dong-E-E-Jiao Co. Ltd., Cl. A4		26,202,089		179,513,340

10       OPPENHEIMER DEVELOPING MARKETS FUND

	Shares		Value
Pharmaceuticals (Continued)
Hutchison China MediTech Ltd., ADR1		3,656,980	$	95,410,608
Jiangsu Hengrui Medicine Co. Ltd., Cl. A5		9,083,634		97,542,091
Jiangsu Hengrui Medicine Co. Ltd., Cl. A4,5		76,967,837		828,321,112
				1,200,787,151
Industrials—5.1%
Air Freight & Couriers—1.2%
ZTO Express Cayman, Inc., ADR		23,247,987		462,169,982
Industrial Conglomerates—2.5%
Jardine Strategic Holdings Ltd.		13,467,948		531,662,628
SM Investments Corp.		26,656,257		485,137,950
				1,016,800,578
Transportation Infrastructure—1.4%
DP World Ltd.		21,923,826		351,013,082
Grupo Aeroportuario del Sureste SAB de CV, Cl. B		12,082,161		204,886,792
				555,899,874
Information Technology—7.7%
Electronic Equipment, Instruments, & Components—0.6%
Sunny Optical Technology Group Co. Ltd.		20,220,100		238,763,485
IT Services—1.1%
StoneCo Ltd., Cl. A1		288,450		8,771,765
Tata Consultancy Services Ltd.		15,306,736		427,533,766
				436,305,531
Semiconductors & Semiconductor Equipment—4.9%
Taiwan Semiconductor Manufacturing Co. Ltd.		255,607,429		1,964,568,260
Technology Hardware, Storage & Peripherals—1.1%
Samsung Electronics Co. Ltd.		10,340,398		412,738,683

	Shares		Value
Materials—6.9%
Construction Materials—1.1%
Indocement Tunggal Prakarsa Tbk PT		125,325,579	$	171,546,104
Odisha Cement Ltd.1		5,598,629		90,772,942
UltraTech Cement Ltd.		3,599,657		193,803,282
				456,122,328
Metals & Mining—5.8%
Glencore plc1		352,998,599		1,425,997,624
Grupo Mexico SAB de CV		214,845,468		538,077,507
Polyus PJSC, GDR3		2,440,700		100,025,170
Vale SA, Cl. B, Sponsored ADR		20,174,300		251,775,264
				2,315,875,565
Total Common Stocks (Cost $27,339,474,903)				37,745,568,240
Preferred Stocks—1.7%
Grab Holdings, Inc., H Shares, Preference1,2,6		65,391,294		403,000,006
Xiaoju Kuaizhi, Inc., Series A, Preference1,2,6		2,615,945		125,539,200
Xiaoju Kuaizhi, Inc., Series A1, Preference1,2,6		2,083,333		99,979,151
Xiaoju Kuaizhi, Inc., Series B, Preference1,2,6		981,699		47,111,735
Zee Entertainment Enterprises Ltd., 6% Cum.Non-Cv.2		189,591,305		21,031,270
Total Preferred Stocks (Cost $662,163,513)				696,661,362

11       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED

STATEMENT OF INVESTMENTSUnaudited / Continued

	Shares		Value
Investment Company—3.5%
Oppenheimer Institutional Government Money Market Fund, Cl. E, 2.37%2,7(Cost $1,381,235,072)		1,381,235,072	$	1,381,235,072
Total Investments, at Value (Cost $29,382,873,488)		99.8%		39,823,464,674
Net Other Assets (Liabilities)		0.2		65,901,175
Net Assets		100.0%	$	39,889,365,849

Footnotes to Consolidated Statement of Investments

1.Non-income producing security.

2. Is or was an affiliate, as defined in the Investment Company Act of 1940, as amended, at or during the reporting period, by virtue of the Fund owning at least 5% of the voting securities of the issuer or as a result of the Fund and the issuer having the same investment adviser. Transactions during the reporting period in which the issuer was an affiliate are as follows:

	Shares August 31, 2018		Gross Additions		Gross Reductions		Shares February 28, 2019
Common Stock
Beverages
Anadolu Efes Biracilik Ve Malt Sanayii AS		38,338,430		—		—		38,338,430
Biotechnology
Shanghai Junshi Biosciences Co. Ltd., Cl. H		—		15,407,000		413,000		14,994,000
Commercial Banks
Grupo Aval Acciones y Valores SA, ADR		27,098,977		—		—		27,098,977
Health Care Providers & Services
Apollo Hospitals Enterprise Ltd.a		10,982,511		—		9,904,482		1,078,029
Sinopharm Group Co. Ltd., Cl. H		166,180,000		—		24,152,800		142,027,200
Hotels, Restaurants & Leisure
Alsea SAB de CV		—		63,950,859		—		63,950,859
Huazhu Group Ltd., ADR		23,141,037		1,981,709		—		25,122,746
Interactive Media & Services
Yandex NV, Cl. A		11,817,570		3,616,260		—		15,433,830
Media
Zee Entertainment Enterprises Ltd.		65,300,739		3,343,864		—		68,644,603
Multiline Retail
Lojas Americanas SA		98,235,400		—		11,050,800		87,184,600
Preferred Stock
Grab Holdings, Inc., H Shares, Preference		65,391,294		—		—		65,391,294
Xiaoju Kuaizhi, Inc., Series A, Preference		2,615,945		—		—		2,615,945

12       OPPENHEIMER DEVELOPING MARKETS FUND

Footnotes to Consolidated Statement of Investments (Continued)

	Shares August 31, 2018			Gross Additions		Gross Reductions		Shares February 28, 2019
Xiaoju Kuaizhi, Inc., Series A1, Preference		2,083,333			—		—		2,083,333
Xiaoju Kuaizhi, Inc., Series B, Preference		981,699			—		—		981,699
Zee Entertainment Enterprises Ltd., 6% Cum.Non-Cv.		189,591,305			—		—		189,591,305
Investment Company
Oppenheimer Institutional Government Money Market Fund, Cl. E		807,331,417			3,786,385,154		3,212,481,499		1,381,235,072
	Value			Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)
Common Stock
Beverages
Anadolu Efes Biracilik Ve Malt Sanayii AS	$	144,098,727		$	—	$	—	$	22,085,595
Biotechnology
Shanghai Junshi Biosciences Co. Ltd., Cl. H		42,022,740			—		92,350		4,441,908
Commercial Banks
Grupo Aval Acciones y Valores SA, ADR		209,475,092			4,062,053		—		(4,877,816)
Health Care Providers & Services
Apollo Hospitals Enterprise Ltd.a		—	b		708,278		3,176,135		(13,838,477)
Sinopharm Group Co. Ltd., Cl. H		634,432,965			—		5,016,087		(81,926,907)
Hotels, Restaurants & Leisure
Alsea SAB de CV		161,888,735			—		—		(2,278,601)
Huazhu Group Ltd., ADR		881,054,702			7,903,621		—		19,013,796
Interactive Media & Services
Yandex NV, Cl. A		530,923,752			—		—		41,499,965
Media
Zee Entertainment Enterprises Ltd.		450,752,956			—		—		(30,234,975)
Multiline Retail
Lojas Americanas SA		462,134,203			1,496,455		(9,888,264)		150,855,297
Preferred Stock
Grab Holdings, Inc., H Shares, Preference		403,000,006			297,077		—		—
Xiaoju Kuaizhi, Inc., Series A, Preference		125,539,200			—		—		2,145,075
Xiaoju Kuaizhi, Inc., Series A1, Preference		99,979,151			—		—		1,708,333
Xiaoju Kuaizhi, Inc., Series B, Preference		47,111,735			—		—		804,993
Zee Entertainment Enterprises Ltd., 6% Cum.Non-Cv.		21,031,270			—		—		47,618
Investment Company

13       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED

STATEMENT OF INVESTMENTSUnaudited / Continued

Footnotes to Consolidated Statement of Investments (Continued)

	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)
Oppenheimer Institutional Government Money Market Fund, Cl. E	$	1,381,235,072	$	11,552,573	$	—	$	—
Total	$	5,594,680,306	$	26,020,057	$	(1,603,692)	$	109,445,804

a. No longer affiliate at period end.

b. The security is no longer an affiliate, therefore, the value has been excluded from this table.

3. Represents securities sold under Rule 144A, which are exempt from registration under the Securities Act of 1933, as amended. These securities have been determined to be liquid under guidelines established by the Board of Trustees. These securities amount to $1,023,510,061 or 2.57% of the Fund’s net assets at period end.

4. All or a portion of this security is owned by the subsidiary. See Note 2 of the accompanying Consolidated Notes.

5. The Fund holds securities which have been issued by the same entity and that trade on separate exchanges.

6. The value of this security was determined using significant unobservable inputs. See Note 3 of the accompanying Consolidated Notes.

7. Rate shown is the7-day yield at period end.

Distribution of investments representing geographic holdings, as a percentage of total investments at value, is as follows:

Geographic Holdings	Value		Percent
China	$	9,352,152,306		23.5%
India		4,064,738,002		10.2
Russia		2,945,402,687		7.4
Hong Kong		2,574,524,043		6.5
Mexico		2,450,733,720		6.1
France		2,372,963,708		6.0
Brazil		1,973,381,209		5.0
Taiwan		1,964,568,260		4.9
South Korea		1,839,289,791		4.6
United States		1,803,605,431		4.6
Philippines		1,429,246,620		3.6
Switzerland		1,425,997,623		3.6
South Africa		932,698,972		2.3
Italy		606,390,069		1.5
Turkey		593,717,401		1.5
Argentina		549,323,031		1.4
United Arab Emirates		519,504,918		1.3
Peru		510,491,917		1.2
Chile		417,540,891		1.0
Singapore		403,000,006		1.0
Indonesia		392,072,170		1.0
Colombia		209,475,092		0.5
Thailand		184,225,959		0.5
Egypt		183,810,819		0.5
Vietnam		124,456,192		0.3
Cayman Islands		153,837		0.0
Total	$	39,823,464,674		100.0%

See accompanying Notes to Consolidated Financial Statements.

14       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED STATEMENT OF

ASSETS AND LIABILITIESFebruary 28, 2019 Unaudited

Assets
Investments, at value—see accompanying consolidated statement of investments:
Unaffiliated companies (cost $24,668,669,714)	$	34,228,784,368
Affiliated companies (cost $4,714,203,774)		5,594,680,306
		39,823,464,674
Cash		53,120,574
Cash—foreign currencies (cost $21,461,896)		21,919,918
Receivables and other assets:
Investments sold		81,528,038
Shares of beneficial interest sold		56,891,718
Dividends		26,024,774
Other		1,675,126
Total assets		40,064,624,822
Liabilities
Payables and other liabilities:
Investments purchased		114,466,843
Shares of beneficial interest redeemed		48,759,390
Trustees’ compensation		1,785,216
Distribution and service plan fees		1,175,252
Foreign capital gains tax		1,134,873
Shareholder communications		12,676
Other		7,924,723
Total liabilities		175,258,973
Net Assets	$	39,889,365,849
Composition of Net Assets
Paid-in capital	$	30,356,440,094
Total distributable earnings		9,532,925,755
Net Assets	$	39,889,365,849

15       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED STATEMENT OF

ASSETS AND LIABILITIESUnaudited / Continued

Net Asset Value Per Share
Class A Shares:
Net asset value and redemption price per share (based on net assets of $4,942,749,514 and 116,963,540 shares of beneficial interest outstanding)	$	42.26
Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	44.84
Class C Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $748,797,876 and 19,060,464 shares of beneficial interest outstanding)	$	39.29
Class I Shares:
Net asset value, redemption price and offering price per share (based on net assets of $15,267,516,113 and 366,672,543 shares of beneficial interest outstanding)	$	41.64
Class R Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $519,585,760 and 12,794,382 shares of beneficial interest outstanding)	$	40.61
Class Y Shares:
Net asset value, redemption price and offering price per share (based on net assets of $18,410,716,586 and 442,150,397 shares of beneficial interest outstanding)	$	41.64

See accompanying Notes to Consolidated Financial Statements.

16       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED STATEMENT OF

OPERATIONSFor the Six Months Ended February 28, 2019 Unaudited

Investment Income
Dividends:
Unaffiliated companies (net of foreign withholding taxes of $17,616,110)	$	164,822,070
Affiliated companies (net of foreign withholding taxes of $301,343)		26,020,057
Interest		820,006
Total investment income		191,662,133
Expenses
Management fees		141,072,061
Distribution and service plan fees:
Class A		5,856,698
Class C		3,666,972
Class R		1,282,462
Transfer and shareholder servicing agent fees:
Class A		4,625,169
Class C		715,747
Class I		2,054,339
Class R		500,714
Class Y		16,362,472
Shareholder communications:
Class A		22,220
Class C		4,577
Class I		29,977
Class R		675
Class Y		62,039
Custodian fees and expenses		8,640,973
Borrowing fees		493,791
Trustees’ compensation		273,321
Other		3,210,322
Total expenses		188,874,529
Less reduction to custodian expenses		(113,794)
Less waivers and reimbursements of expenses		(513,616)
Net expenses		188,247,119
Net Investment Income		3,415,014

17       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED STATEMENT OF

OPERATIONSUnaudited / Continued

Realized and Unrealized Gain (Loss)
Net realized loss on:
Investment transactions in:
Unaffiliated companies	$	(269,180,176)
Affiliated companies		(1,603,692)
Foreign currency transactions		(28,884,013)
Net realized loss		(299,667,881)
Net change in unrealized appreciation/(depreciation) on:
Investment transactions in:
Unaffiliated companies		562,729,743
Affiliated companies		109,445,804
Translation of assets and liabilities denominated in foreign currencies		46,486,327
Net change in unrealized appreciation/(depreciation)		718,661,874
Net Increase in Net Assets Resulting from Operations	$	422,409,007

See accompanying Notes to Consolidated Financial Statements.

18       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS

		Six Months Ended February 28, 2019 (Unaudited)		Year Ended August 31, 20181
Operations
Net investment income		$	3,415,014	$	143,722,639
Net realized gain (loss)			(299,667,881)		2,682,724,173
Net change in unrealized appreciation/(depreciation)			718,661,874		(2,198,636,821)
Net increase in net assets resulting from operations			422,409,007		627,809,991
Dividends and/or Distributions to Shareholders
Dividends and distributions declared:
Class A			(12,939,870)		(18,919,405)
Class B2			—		—
Class C			—		—
Class I			(107,242,317)		(92,634,631)
Class R			—		(743,812)
Class Y			(100,145,148)		(104,289,090)
Total dividends and distributions declared			(220,327,335)		(216,586,938)
Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A			(340,076,235)		(1,193,123,304)
Class B2			—		(19,647,055)
Class C			(76,867,794)		(160,861,678)
Class I	��		1,167,198,237		2,377,253,137
Class R			(65,907,011)		(107,346,421)
Class Y			427,400,071		188,006,405
Total beneficial interest transactions			1,111,747,268		1,084,281,084
Net Assets
Total increase			1,313,828,940		1,495,504,137
Beginning of period			38,575,536,909		37,080,032,772
End of period		$	39,889,365,849	$	38,575,536,909

1. Prior period amounts have been conformed to current year presentation. See Notes to Consolidated Financial Statements, Note 2– New Accounting Pronouncements for further details.

2. Effective June 1, 2018, all Class B shares converted to Class A shares.

See accompanying Notes to Consolidated Financial Statements.

19       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED FINANCIAL HIGHLIGHTS

Class A	Six Months Ended February 28, 2019 (Unaudited)	Year Ended August 31, 2018	Year Ended August 31, 2017	Year Ended August 31, 2016	Year Ended August 31, 2015	Year Ended August 29, 20141
Per Share Operating Data
Net asset value, beginning of period	$42.01	$41.49	$33.45	$30.06	$41.30		$33.94
Income (loss) from investment operations:
Net investment income (loss)2	(0.05)	0.06	0.13	0.12	0.17		0.14
Net realized and unrealized gain (loss)	0.41	0.59	7.98	3.40	(10.71)		7.44
Total from investment operations	0.36	0.65	8.11	3.52	(10.54)		7.58
Dividends and/or distributions to shareholders:
Dividends from net investment income	(0.11)	(0.13)	(0.07)	(0.13)	(0.10)		(0.04)
Distributions from net realized gain	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Total dividends and/or distributions to shareholders	(0.11)	(0.13)	(0.07)	(0.13)	(0.70)		(0.22)
Net asset value, end of period	$42.26	$42.01	$41.49	$33.45	$30.06		$41.30
Total Return, at Net Asset Value3	0.84%	1.59%	24.32%	11.74%	(25.84)%		22.38%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$4,942,749	$5,277,791	$6,350,957	$6,574,857	$7,679,026		$12,573,313
Average net assets (in thousands)	$4,781,522	$6,132,474	$6,236,473	$6,903,922	$10,303,699		$13,256,077
Ratios to average net assets:4
Net investment income (loss)	(0.23)%	0.13%	0.37%	0.38%	0.47%		0.36%
Expenses excluding specific expenses listed below	1.28%	1.29%	1.32%	1.32%	1.31%		1.32%
Interest and fees from borrowings	0.00%5	0.00%5	0.00%5	0.00%5	0.00%5		0.00%
Total expenses6	1.28%	1.29%	1.32%	1.32%	1.31%		1.32%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses	1.28%7	1.28%	1.31%	1.32%7	1.30%		1.31%
Portfolio turnover rate	12%	36%	33%	18%	36%		26%

20       OPPENHEIMER DEVELOPING MARKETS FUND

1. Represents the last business day of the Fund’s reporting period.

2. Per share amounts calculated based on the average shares outstanding during the period.

3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

4. Annualized for periods less than one full year.

5. Less than 0.005%.

6. Total expenses including indirect expenses from affiliated fund fees and expenses were as follows:

Six Months Ended February 28, 2019	1.28%
Year Ended August 31, 2018	1.29%
Year Ended August 31, 2017	1.32%
Year Ended August 31, 2016	1.32%
Year Ended August 31, 2015	1.31%
Year Ended August 29, 2014	1.33%

7. Waiver was less than 0.005%.

See accompanying Notes to Consolidated Financial Statements.

21       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED FINANCIAL HIGHLIGHTSContinued

Class C	Six Months Ended February 28, 2019 (Unaudited)	Year Ended August 31, 2018	Year Ended August 31, 2017	Year Ended August 31, 2016	Year Ended August 31, 2015	Year Ended August 29, 20141
Per Share Operating Data
Net asset value, beginning of period	$39.10	$38.79	$31.44	$28.35	$39.17		$32.40
Income (loss) from investment operations:
Net investment loss2	(0.18)	(0.25)	(0.13)	(0.11)	(0.10)		(0.13)
Net realized and unrealized gain (loss)	0.37	0.56	7.48	3.20	(10.12)		7.08
Total from investment operations	0.19	0.31	7.35	3.09	(10.22)		6.95
Dividends and/or distributions to shareholders:
Dividends from net investment income	0.00	0.00	0.00	0.00	0.00		0.00
Distributions from net realized gain	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Total dividends and/or distributions to shareholders	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Net asset value, end of period	$39.29	$39.10	$38.79	$31.44	$28.35		$39.17
Total Return, at Net Asset Value3	0.48%	0.80%	23.38%	10.90%	(26.39)%		21.50%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$748,798	$826,481	$973,031	$1,046,894	$1,311,171		$2,190,364
Average net assets (in thousands)	$739,784	$943,157	$964,547	$1,114,383	$1,785,113		$2,180,118
Ratios to average net assets:4
Net investment loss	(0.98)%	(0.62)%	(0.39)%	(0.39)%	(0.29)%		(0.37)%
Expenses excluding specific expenses listed below	2.04%	2.05%	2.07%	2.07%	2.06%		2.04%
Interest and fees from borrowings	0.00%5	0.00%5	0.00%5	0.00%5	0.00%5		0.00%
Total expenses6	2.04%	2.05%	2.07%	2.07%	2.06%		2.04%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses	2.04%7	2.04%	2.06%	2.07%7	2.05%		2.03%
Portfolio turnover rate	12%	36%	33%	18%	36%		26%

22       OPPENHEIMER DEVELOPING MARKETS FUND

1. Represents the last business day of the Fund’s reporting period.

2. Per share amounts calculated based on the average shares outstanding during the period.

3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

4. Annualized for periods less than one full year.

5. Less than 0.005%.

6. Total expenses including indirect expenses from affiliated fund fees and expenses were as follows:

Six Months Ended February 28, 2019	2.04%
Year Ended August 31, 2018	2.05%
Year Ended August 31, 2017	2.07%
Year Ended August 31, 2016	2.07%
Year Ended August 31, 2015	2.06%
Year Ended August 29, 2014	2.05%

7. Waiver was less than 0.005%.

See accompanying Notes to Consolidated Financial Statements.

23       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED FINANCIAL HIGHLIGHTSContinued

Class I	Six Months Ended February 28, 2019 (Unaudited)	Year Ended August 31, 2018	Year Ended August 31, 2017	Year Ended August 31, 2016	Year Ended August 31, 2015	Year Ended August 29, 20141
Per Share Operating Data
Net asset value, beginning of period	$41.52	$41.01	$33.09	$29.77	$40.94		$33.65
Income (loss) from investment operations:
Net investment income2	0.04	0.23	0.31	0.26	0.34		0.33
Net realized and unrealized gain (loss)	0.38	0.59	7.84	3.36	(10.61)		7.35
Total from investment operations	0.42	0.82	8.15	3.62	(10.27)		7.68
Dividends and/or distributions to shareholders:
Dividends from net investment income	(0.30)	(0.31)	(0.23)	(0.30)	(0.30)		(0.21)
Distributions from net realized gain	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Total dividends and/or distributions to shareholders	(0.30)	(0.31)	(0.23)	(0.30)	(0.90)		(0.39)
Net asset value, end of period	$41.64	$41.52	$41.01	$33.09	$29.77		$40.94
Total Return, at Net Asset Value3	1.06%	2.00%	24.84%	12.22%	(25.50)%		22.95%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$15,267,516	$13,987,540	$11,559,582	$7,861,500	$6,201,064		$7,445,448
Average net assets (in thousands)	$13,824,433	$13,484,000	$9,305,452	$6,593,711	$6,961,648		$3,901,775
Ratios to average net assets:4
Net investment income	0.18%	0.55%	0.87%	0.87%	0.95%		0.87%
Expenses excluding specific expenses listed below	0.87%	0.87%	0.88%	0.88%	0.87%		0.86%
Interest and fees from borrowings	0.00%5	0.00%5	0.00%5	0.00%5	0.00%5		0.00%
Total expenses6	0.87%	0.87%	0.88%	0.88%	0.87%		0.86%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses	0.87%7	0.87%7	0.88%7	0.88%7	0.86%		0.85%
Portfolio turnover rate	12%	36%	33%	18%	36%		26%

24       OPPENHEIMER DEVELOPING MARKETS FUND

1. Represents the last business day of the Fund’s reporting period.

2. Per share amounts calculated based on the average shares outstanding during the period.

3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

4. Annualized for periods less than one full year.

5. Less than 0.005%.

6. Total expenses including indirect expenses from affiliated fund fees and expenses were as follows:

Six Months Ended February 28, 2019	0.87%
Year Ended August 31, 2018	0.87%
Year Ended August 31, 2017	0.88%
Year Ended August 31, 2016	0.88%
Year Ended August 31, 2015	0.87%
Year Ended August 29, 2014	0.87%

7. Waiver was less than 0.005%.

See accompanying Notes to Consolidated Financial Statements.

25       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED FINANCIAL HIGHLIGHTSContinued

Class R	Six Months Ended February 28, 2019 (Unaudited)	Year Ended August 31, 2018	Year Ended August 31, 2017	Year Ended August 31, 2016	Year Ended August 31, 2015	Year Ended August 29, 20141
Per Share Operating Data
Net asset value, beginning of period	$40.32	$39.84	$32.13	$28.88	$39.74		$32.72
Income (loss) from investment operations:
Net investment income (loss)2	(0.09)	(0.05)	0.05	0.04	0.08		0.04
Net realized and unrealized gain (loss)	0.38	0.58	7.66	3.27	(10.30)		7.16
Total from investment operations	0.29	0.53	7.71	3.31	(10.22)		7.20
Dividends and/or distributions to shareholders:
Dividends from net investment income	0.00	(0.05)	(0.00)3	(0.06)	(0.04)		0.00
Distributions from net realized gain	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Total dividends and/or distributions to shareholders	0.00	(0.05)	(0.00)	(0.06)	(0.64)		(0.18)
Net asset value, end of period	$40.61	$40.32	$39.84	$32.13	$28.88		$39.74
Total Return, at Net Asset Value4	0.72%	1.32%	24.01%	11.47%	(26.03)%		22.05%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$519,586	$585,385	$680,861	$634,007	$657,581		$972,479
Average net assets (in thousands)	$517,440	$667,630	$626,788	$627,034	$832,613		$922,384
Ratios to average net assets:5
Net investment income (loss)	(0.48)%	(0.12)%	0.14%	0.14%	0.23%		0.10%
Expenses excluding specific expenses listed below	1.53%	1.55%	1.57%	1.57%	1.56%		1.64%
Interest and fees from borrowings	0.00%6	0.00%6	0.00%6	0.00%6	0.00%6		0.00%
Total expenses7	1.53%	1.55%	1.57%	1.57%	1.56%		1.64%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses	1.53%8	1.54%	1.56%	1.57%8	1.55%		1.58%
Portfolio turnover rate	12%	36%	33%	18%	36%		26%

26       OPPENHEIMER DEVELOPING MARKETS FUND

1. Represents the last business day of the Fund’s reporting period.

2. Per share amounts calculated based on the average shares outstanding during the period.

3. Less than $0.005 per share.

4. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

5. Annualized for periods less than one full year.

6. Less than 0.005%.

7. Total expenses including indirect expenses from affiliated fund fees and expenses were as follows:

Six Months Ended February 28, 2019	1.53%
Year Ended August 31, 2018	1.55%
Year Ended August 31, 2017	1.57%
Year Ended August 31, 2016	1.57%
Year Ended August 31, 2015	1.56%
Year Ended August 29, 2014	1.65%

8. Waiver was less than 0.005%.

See accompanying Notes to Consolidated Financial Statements.

27       OPPENHEIMER DEVELOPING MARKETS FUND

CONSOLIDATED FINANCIAL HIGHLIGHTSContinued

Class Y	Six Months Ended February 28, 2019 (Unaudited)	Year Ended August 31, 2018	Year Ended August 31, 2017	Year Ended August 31, 2016	Year Ended August 31, 2015	Year Ended August 29, 20141
Per Share Operating Data
Net asset value, beginning of period	$41.48	$40.98	$33.06	$29.73	$40.88		$33.62
Income (loss) from investment operations:
Net investment income2	0.003	0.16	0.24	0.19	0.26		0.25
Net realized and unrealized gain (loss)	0.39	0.59	7.85	3.36	(10.59)		7.35
Total from investment operations	0.39	0.75	8.09	3.55	(10.33)		7.60
Dividends and/or distributions to shareholders:
Dividends from net investment income	(0.23)	(0.25)	(0.17)	(0.22)	(0.22)		(0.16)
Distributions from net realized gain	0.00	0.00	0.00	0.00	(0.60)		(0.18)
Total dividends and/or distributions to shareholders	(0.23)	(0.25)	(0.17)	(0.22)	(0.82)		(0.34)
Net asset value, end of period	$41.64	$41.48	$40.98	$33.06	$29.73		$40.88
Total Return, at Net Asset Value4	0.98%	1.82%	24.61%	12.04%	(25.66)%		22.72%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$18,410,717	$17,898,340	$17,496,988	$13,551,480	$15,358,492		$21,476,284
Average net assets (in thousands)	$16,929,302	$18,317,515	$14,523,085	$13,507,017	$19,567,341		$19,215,510
Ratios to average net assets:5
Net investment income	0.02%	0.38%	0.67%	0.62%	0.74%		0.67%
Expenses excluding specific expenses listed below	1.03%	1.05%	1.07%	1.07%	1.06%		1.04%
Interest and fees from borrowings	0.00%6	0.00%6	0.00%6	0.00%6	0.00%6		0.00%
Total expenses7	1.03%	1.05%	1.07%	1.07%	1.06%		1.04%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses	1.03%8	1.04%	1.06%	1.07%8	1.05%		1.03%
Portfolio turnover rate	12%	36%	33%	18%	36%		26%

28       OPPENHEIMER DEVELOPING MARKETS FUND

1. Represents the last business day of the Fund’s reporting period.

2. Per share amounts calculated based on the average shares outstanding during the period.

3. Less than $0.005 per share.

4. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

5. Annualized for periods less than one full year.

6. Less than 0.005%.

7. Total expenses including indirect expenses from affiliated fund fees and expenses were as follows:

Six Months Ended February 28, 2019	1.03%
Year Ended August 31, 2018	1.05%
Year Ended August 31, 2017	1.07%
Year Ended August 31, 2016	1.07%
Year Ended August 31, 2015	1.06%
Year Ended August 29, 2014	1.05%

8. Waiver was less than 0.005%.

See accompanying Notes to Consolidated Financial Statements.

29       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSFebruary 28, 2019 Unaudited

1. Organization

Oppenheimer Developing Markets Fund (the “Fund”) is a diversifiedopen-end management investment company registered under the Investment Company Act of 1940 (“1940 Act”), as amended. The Fund’s investment objective is to seek capital appreciation. The Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the“Sub-Adviser”). The Manager has entered into asub-advisory agreement with OFI.

The Fund offers Class A, Class C, Class I, Class R and Class Y shares, and previously offered Class B shares for new purchase through June 29, 2012. Subsequent to that date, no new purchases of Class B shares were permitted. Reinvestment of dividend and/or capital gain distributions and exchanges of Class B shares into and from other Oppenheimer funds were permitted through May 31, 2018. Effective June 1, 2018 (the “Conversion Date”), all Class B shares converted to Class A shares. Class A shares are sold at their offering price, which is normally net asset value plus afront-end sales charge. Class C and Class R shares are sold, and Class B shares were sold, without afront-end sales charge but may be subject to a contingent deferred sales charge (“CDSC”). Class R shares are sold only through retirement plans. Retirement plans that offer Class R shares may impose charges on those accounts. Class I and Class Y shares are sold to certain institutional investors or intermediaries without either afront-end sales charge or a CDSC, however, the intermediaries may impose charges on their accountholders who beneficially own Class I and Class Y shares. All classes of shares have identical rights and voting privileges with respect to the Fund in general and exclusive voting rights on matters that affect that class alone. Earnings, net assets and net asset value per share may differ due to each class having its own expenses, such as transfer and shareholder servicing agent fees and shareholder communications, directly attributable to that class. Class A, C and R shares have, and Class B shares had, separate distribution and/or service plans under which they pay, and Class B shares paid, fees. Class I and Class Y shares do not pay such fees. Previously issued Class B shares automatically converted to Class A shares 72 months after the date of purchase.

The following is a summary of significant accounting policies followed in the Fund’s preparation of financial statements in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”).

2. Significant Accounting Policies

Security Valuation.All investments in securities are recorded at their estimated fair value, as described in Note 3.

Basis for Consolidation.The Fund has established a private vehicle, OFI Global China Fund,

LLC (the “Subsidiary”), which is wholly-owned and controlled by the Fund organized under laws of Delaware. The Fund and Subsidiary are both managed by the Manager. The Fund may invest up to 10% of its total net assets in the Subsidiary. The Subsidiary invests significantly in classA-shares of Chinese companies (“China A Shares”). The Fund applies its investment restrictions and compliance policies and procedures, on a look-through basis, to

30       OPPENHEIMER DEVELOPING MARKETS FUND

2. Significant Accounting Policies (Continued)

the Subsidiary.

The financial statements have been consolidated and include accounts of the Fund and the Subsidiary. Accordingly, all inter-company transactions and balances have been eliminated. At period end, the Fund owned 29,428,285 shares with net assets of $1,027,995,007 in the Subsidiary.

Other financial information at period end:

Total market value of investments	$	1,007,834,452
Net assets	$	1,027,995,007
Net income (loss)	$	87,347
Net realized gain (loss)	$	62,429,145
Net change in unrealized appreciation (depreciation)	$	52,340,547

Foreign Currency Translation.The books and records of the Fund are maintained in U.S. dollars. Any foreign currency amounts are translated into U.S. dollars on the following basis:

(1) Value of investment securities, other assets and liabilities — at the exchange rates prevailing at market close as described in Note 3.

(2) Purchases and sales of investment securities, income and expenses — at the rates of exchange prevailing on the respective dates of such transactions.

Although the net assets and the values are presented at the foreign exchange rates at market close, the Fund does not isolate the portion of the results of operations resulting from changes in foreign exchange rates on investments from the fluctuations arising from changes in prices of securities held. Such fluctuations are included with the net realized and unrealized gains or losses from investments shown in the Consolidated Statement of Operations.

For securities, which are subject to foreign withholding tax upon disposition, realized and unrealized gains or losses on such securities are recorded net of foreign withholding tax.

Reported net realized foreign exchange gains or losses arise from sales of foreign currencies, currency gains or losses realized between the trade and settlement dates on securities transactions, the difference between the amounts of dividends, interest, and foreign withholding tax reclaims recorded on the Fund’s books, and the U.S. dollar equivalent of the amounts actually received or paid. Net unrealized foreign exchange gains and losses arise from changes in the value of assets and liabilities other than investments in securities, resulting from changes in the exchange rate.

Allocation of Income, Expenses, Gains and Losses.Income, expenses (other than those attributable to a specific class), gains and losses are allocated on a daily basis to each class of shares based upon the relative proportion of net assets represented by such class. Operating expenses directly attributable to a specific class are charged against the operations of that class.

Dividends and Distributions to Shareholders. Dividends and distributions to shareholders, which are determined in accordance with income tax regulations and may differ

31       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

2. Significant Accounting Policies (Continued)

from U.S. GAAP, are recorded on theex-dividend date. Income and capital gain distributions, if any, are declared and paid annually or at other times as determined necessary by the Manager.

The tax character of distributions is determined as of the Fund’s fiscal year end. Therefore, a portion of the Fund’s distributions made to shareholders prior to the Fund’s fiscal year end may ultimately be categorized as a tax return of capital.

Investment Income.Dividend income is recorded on theex-dividend date or uponex-dividend notification in the case of certain foreign dividends where theex-dividend date may have passed.Non-cash dividends included in dividend income, if any, are recorded at the fair value of the securities received. Withholding taxes on foreign dividends, if any, and capital gains taxes on foreign investments, if any, have been provided for in accordance with the Fund’s understanding of the applicable tax rules and regulations. Interest income, if any, is recognized on an accrual basis. Discount and premium, which are included in interest income on the Consolidated Statement of Operations, are amortized or accreted daily.

Custodian Fees. “Custodian fees and expenses” in the Consolidated Statement of Operations may include interest expense incurred by the Fund on any cash overdrafts of its custodian account during the period. Such cash overdrafts may result from the effects of failed trades in portfolio securities and from cash outflows resulting from unanticipated shareholder redemption activity. The Fund pays interest to its custodian on such cash overdrafts, to the extent they are not offset by positive cash balances maintained by the Fund, at a rate equal to the Federal Funds Rate plus 2.00%. The “Reduction to custodian expenses” line item, if applicable, represents earnings on cash balances maintained by the Fund during the period. Such interest expense and other custodian fees may be paid with these earnings.

Security Transactions. Security transactions are recorded on the trade date. Realized gains and losses on securities sold are determined on the basis of identified cost.

Indemnifications.The Fund’s organizational documents provide current and former Trustees and officers with a limited indemnification against liabilities arising in connection with the performance of their duties to the Fund. In the normal course of business, the Fund may also enter into contracts that provide general indemnifications. The Fund’s maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against the Fund. The risk of material loss from such claims is considered remote.

Federal Taxes.The Fund intends to comply with provisions of the Internal Revenue Code applicable to regulated investment companies and to distribute substantially all of its investment company taxable income to shareholders. Therefore, no federal income or excise tax provision is required. The Fund files income tax returns in U.S. federal and applicable state jurisdictions. The statute of limitations on the Fund’s tax return filings generally remains open for the three preceding fiscal reporting period ends. The Fund has analyzed its tax positions for

32       OPPENHEIMER DEVELOPING MARKETS FUND

2. Significant Accounting Policies (Continued)

the fiscal year ended August 31, 2018, including open tax years, and does not believe there are any uncertain tax positions requiring recognition in the Fund’s financial statements.    

During the fiscal year ended August 31, 2018, the Fund utilized $2,590,041,165 ofcapital loss carryforwards to offset capital gains realized in that fiscal year. Capital losses with no expiration will be carried forward to future years if not offset by gains.

At period end, it is estimated that the capital loss carryforwards would be $781,415,870, which will not expire.The estimated capital loss carryforward represents the carryforward as of the end of the last fiscal year, increased or decreased by capital losses or gains realized in the first six months of the current fiscal year. During the reporting period, it is estimated that the Fund will not utilize any capital loss carryforward to offset realized capital gains.

Net investment income (loss) and net realized gain (loss) may differ for financial statement and tax purposes. The character of dividends and distributions made during the fiscal year from net investment income or net realized gains are determined in accordance with federal income tax requirements, which may differ from the character of net investment income or net realized gains presented in those financial statements in accordance with U.S. GAAP. Also, due to timing of dividends and distributions, the fiscal year in which amounts are distributed may differ from the fiscal year in which the income or net realized gain was recorded by the Fund.

The aggregate cost of securities and other investments and the composition of unrealized appreciation and depreciation of securities and other investments for federal income tax purposes at period end are noted in the following table. The primary difference between book and tax appreciation or depreciation of securities and other investments, if applicable, is attributable to the tax deferral of losses or tax realization of financial statement unrealized gain or loss.

Federal tax cost of securities	$	29,408,297,787
Federal tax cost of other investments		21,461,896
Total federal tax cost	$	29,429,759,683
Gross unrealized appreciation	$	13,348,838,294
Gross unrealized depreciation		(2,934,431,208)
Net unrealized appreciation	$	10,414,407,086

Certain foreign countries impose a tax on capital gains which is accrued by the Fund based on unrealized appreciation, if any, on affected securities. The tax is paid when the gain is realized.

Use of Estimates. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates.

New Accounting Pronouncements. In March 2017, Financial Accounting Standards Board

33       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

2. Significant Accounting Policies (Continued)

(“FASB”) issued Accounting Standards Update (“ASU”), ASU2017-08. This provides guidance related to the amortization period for certain purchased callable debt securities held at a premium. The ASU is effective for annual periods beginning after December 15, 2018, and interim periods within those annual periods. The Manager has evaluated the impacts of these changes on the financial statements and there are no material impacts.

During August 2018, the Securities and Exchange Commission (the “SEC”) issued Final Rule ReleaseNo. 33-10532 (the “Rule”), Disclosure Update and Simplification. The rule amends certain financial statement disclosure requirements to conform to U.S. GAAP. The amendments to Rule6-04.17 of RegulationS-X (balance sheet) remove the requirement to separately state the book basis components of net assets: undistributed (over-distribution of) net investment income (“UNII”), accumulated undistributed net realized gains (losses), and net unrealized appreciation (depreciation) at the balance sheet date. Instead, consistent with U.S. GAAP, funds will be required to disclose total distributable earnings. The amendments to Rule6-09 of RegulationS-X (statement of changes in net assets) remove the requirement to separately state the sources of distributions paid. Instead, consistent with U.S. GAAP, funds will be required to disclose the total amount of distributions paid, except that any tax return of capital must be separately disclosed. The amendments also remove the requirement to parenthetically state the book basis amount of UNII on the statement of changes in net assets. The requirements of the Rule were effective November 5, 2018, and the Fund’s Statement of Assets and Liabilities and Statement of Changes in Net Assets for the current reporting period have been modified accordingly. In addition, certain amounts within the Fund’s Statement of Changes in Net Assets for the prior fiscal period have been modified to conform to the Rule.

3. Securities Valuation

The Fund calculates the net asset value of its shares as of 4:00 P.M. Eastern Time, on each day the New York Stock Exchange (the “Exchange” or “NYSE”) is open for trading, except in the case of a scheduled early closing of the Exchange, in which case the Fund will calculate net asset value of the shares as of the scheduled early closing time of the Exchange.

The Fund’s Board has adopted procedures for the valuation of the Fund’s securities and has delegated theday-to-day responsibility for valuation determinations under those procedures to the Manager. The Manager has established a Valuation Committee which is responsible for determining a fair valuation for any security for which market quotations are not readily available. The Valuation Committee’s fair valuation determinations are subject to review, approval and ratification by the Fund’s Board at least quarterly or more frequently, if necessary.

Valuation Methods and Inputs

Securities are valued primarily using unadjusted quoted market prices, when available, as supplied by third party pricing services or broker-dealers.

The following methodologies are used to determine the market value or the fair value of the types of securities described below:

34       OPPENHEIMER DEVELOPING MARKETS FUND

3. Securities Valuation (Continued)

Equity securities traded on a securities exchange (including exchange-traded derivatives other than futures and futures options) are valued based on the official closing price on the principal exchange on which the security is traded, as identified by the Manager, prior to the time when the Fund’s assets are valued. If the official closing price is unavailable, the security is valued at the last sale price on the principal exchange on which it is traded, or if no sales occurred, the security is valued at the mean between the quoted bid and asked prices.Over-the-counter equity securities are valued at the last published sale price, or if no sales occurred, at the mean between the quoted bid and asked prices. Events occurring after the close of trading on foreign exchanges may result in adjustments to the valuation of foreign securities to more accurately reflect their fair value as of the time when the Fund’s assets are valued.

Shares of a registered investment company that are not traded on an exchange are valued at that investment company’s net asset value per share.

Securities for which market quotations are not readily available, or when a significant event has occurred that would materially affect the value of the security, are fair valued either (i) by a standardized fair valuation methodology applicable to the security type or the significant event as previously approved by the Valuation Committee and the Fund’s Board or (ii) as determined in good faith by the Manager’s Valuation Committee. The Valuation Committee considers all relevant facts that are reasonably available, through either public information or information available to the Manager, when determining the fair value of a security. Those standardized fair valuation methodologies include, but are not limited to, valuing securities at the last sale price or initially at cost and subsequently adjusting the value based on: changes in company specific fundamentals, changes in an appropriate securities index, or changes in the value of similar securities which may be further adjusted for any discounts related to security-specific resale restrictions. When possible, such methodologies use observable market inputs such as unadjusted quoted prices of similar securities, observable interest rates, currency rates and yield curves. The methodologies used for valuing securities are not necessarily an indication of the risks associated with investing in those securities nor can it be assured that the Fund can obtain the fair value assigned to a security if it were to sell the security.

To assess the continuing appropriateness of security valuations, the Manager regularly compares prior day prices and sale prices to the current day prices and challenges those prices exceeding certain tolerance levels with the third party pricing service or broker source. For those securities valued by fair valuations, whether through a standardized fair valuation methodology or a fair valuation determination, the Valuation Committee reviews and affirms the reasonableness of the valuations based on such methodologies and fair valuation determinations on a regular basis after considering all relevant information that is reasonably available.

Classifications

Each investment asset or liability of the Fund is assigned a level at measurement date based on the significance and source of the inputs to its valuation. Various data inputs may be used in determining the value of each of the Fund’s investments as of the reporting period end.

35       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

3. Securities Valuation (Continued)

These data inputs are categorized in the following hierarchy under applicable financial accounting standards:

1) Level1-unadjusted quoted prices in active markets for identical assets or liabilities (including securities actively traded on a securities exchange)

2) Level2-inputs other than unadjusted quoted prices that are observable for the asset or liability (such as unadjusted quoted prices for similar assets and market corroborated inputs such as interest rates, prepayment speeds, credit risks, etc.)

3) Level3-significant unobservable inputs (including the Manager’s own judgments about assumptions that market participants would use in pricing the asset or liability).

The inputs used for valuing securities are not necessarily an indication of the risks associated with investing in those securities.

The Fund classifies each of its investments in investment companies which are publicly offered as Level 1. Investment companies that are not publicly offered, if any, are classified as Level 2 in the fair value hierarchy.

The table below categorizes amounts that are included in the Fund’s Consolidated Statement of Assets and Liabilities at period end based on valuation input level:

	Level 1— Unadjusted Quoted Prices		Level 2— Other Significant Observable Inputs		Level 3— Significant Unobservable Inputs		Value
Assets Table
Investments, at Value:
Common Stocks
Consumer Discretionary	$	6,013,284,580	$	6,467,755,255	$	—	$	12,481,039,835
Consumer Staples		1,338,875,924		1,737,648,890		—		3,076,524,814
Energy		—		1,946,640,973		—		1,946,640,973
Financials		1,287,414,089		8,337,314,786		—		9,624,728,875
Health Care		95,410,608		2,661,978,849		—		2,757,389,457
Industrials		667,056,774		1,367,813,660		—		2,034,870,434
Information Technology		8,771,765		3,043,604,194		—		3,052,375,959
Materials		789,852,771		1,982,145,122		—		2,771,997,893
Preferred Stocks		21,031,270		—		675,630,092		696,661,362
Investment Company		1,381,235,072		—		—		1,381,235,072
Total Assets	$	11,602,932,853	$	27,544,901,729	$	675,630,092	$	39,823,464,674

Forward currency exchange contracts and futures contracts, if any, are reported at their unrealized appreciation/depreciation at measurement date, which represents the change in the contract’s value from trade date. All additional assets and liabilities included in the above table are reported at their market value at measurement date.

The table below shows the transfers between Level 1 and Level 2. The Fund’s policy is to recognize transfers in and transfers out as of the beginning of the reporting period.

36       OPPENHEIMER DEVELOPING MARKETS FUND

3. Securities Valuation (Continued)

	Transfers out of Level 1*		Transfers into Level 2*
Assets Table
Investments, at Value:
Common Stocks
Consumer Staples	$	(642,936,832)	$	642,936,832
Financials		(521,753,032)		521,753,032
Information Technology		(799,952,742)		799,952,742
Total Assets	$	(1,964,642,606)	$	1,964,642,606

*Transfers from Level 1 to Level 2 are a result of a change in pricing methodology to the use of a valuation determined based on observable market information other than quoted prices from an active market due to a lack of available unadjusted quoted prices.

The following is a reconciliation of assets in which significant unobservable inputs (level 3) were used in determining fair value:

	Value as of August 31, 2018		Realized gain (loss)		Change in unrealized appreciation/ depreciation		Accretion/ (amortization) of premium/ discounta
Assets Table
Investments, at Value:
Preferred Stocks	$	670,971,691	$	—	$	4,658,401	$	—
Total Assets	$	670,971,691	$	—	$	4,658,401	$	—

a. Included in net investment income.

	Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Value as of February 28, 2019
Assets Table
Investments, at Value:
Preferred Stocks	$	—	$	—	$	—	$	—	$	675,630,092
Total Assets	$	—	$	—	$	—	$	—	$	675,630,092

The total change in unrealized appreciation/depreciation included in the Consolidated Statement of Operations attributable to Level 3 investments still held at period end:

	Change in unrealized appreciation/ depreciation
Assets Table
Investments, at Value:
Preferred Stocks	$	4,658,401
Total Assets	$	4,658,401

The following table summarizes the valuation techniques and significant unobservable inputs used in determining fair value measurements for those investments classified as Level 3 as of February 28, 2019:

37       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

3. Securities Valuation (Continued)

	Value as of February 28, 2019		Valuation Technique	Unobservable Input		Range of Unobservable Inputs		Unobservable Input Used
Assets Table
Investments, at Value:
Preferred Stocks	$	272,630,086	Weighted Average Transaction Price		Recent Transaction Price	$	46-48.39/share	$	47.99 (a)
Preferred Stocks		403,000,006	Recent Transaction Price		Recent Transaction Price		N/A		$6.1629/share (b)
Total	$	675,630,092

(a) The Fund fair values certain preferred stocks at the weighted average of recent transaction prices occurring within the past two months. The Manager periodically reviews the financial statements and monitors such investments for additional market information or the occurrence of a significant event which would warrant are-evaluation of the security’s fair valuation.

(b) The Fund fair values certain preferred stocks at the most recent transaction price occurring within the past eight months. The Manager periodically reviews the financial statements and monitors such investments for additional market information or the occurrence of a significant event which would warrant are-evaluation of the security’s fair valuation.

4. Investments and Risks

Risks of Foreign Investing.The Fund may invest in foreign securities which are subject to special risks. Securities traded in foreign markets may be less liquid and more volatile than those traded in U.S. markets. Foreign issuers are usually not subject to the same accounting and disclosure requirements that U.S. companies are subject to, which may make it difficult for the Fund to evaluate a foreign company’s operations or financial condition. A change in the value of a foreign currency against the U.S. dollar will result in a change in the U.S. dollar value of investments denominated in that foreign currency and in the value of any income or distributions the Fund may receive on those investments. The value of foreign investments may be affected by exchange control regulations, foreign taxes, higher transaction and other costs, delays in the settlement of transactions, changes in economic or monetary policy in the United States or abroad, expropriation or nationalization of a company’s assets, or other political and economic factors. In addition, due to the inter-relationship of global economies and financial markets, changes in political and economic factors in one country or region could adversely affect conditions in another country or region. Investments in foreign securities may also expose the Fund to time-zone arbitrage risk. Foreign securities may trade on weekends or other days when the Fund does not price its shares. At times, the Fund may emphasize investments in a particular country or region and may be subject to greater risks from adverse events that occur in that country or region. Foreign securities and foreign currencies held in foreign banks and securities depositories may be subject to limited or no regulatory oversight.

Investments in Affiliated Funds. The Fund is permitted to invest in other mutual funds advised by the Manager or an affiliate of the Manager (“Affiliated Funds”). Affiliated Funds

38       OPPENHEIMER DEVELOPING MARKETS FUND

4. Investments and Risks (Continued)

are management investment companies registered under the 1940 Act, as amended. Unless otherwise stated, the Manager is the investment adviser of, and theSub-Adviser provides investment and related advisory services to, the Affiliated Funds. When applicable, the Fund’s investments in Affiliated Funds are included in the Consolidated Statement of Investments. Shares of Affiliated Funds are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of the Affiliated Funds’ expenses, including their management fee. The Manager will waive fees and/or reimburse Fund expenses in an amount equal to the indirect management fees incurred through the Fund’s investment in the Affiliated Funds.

Each of the Affiliated Funds in which the Fund invests has its own investment risks, and those risks can affect the value of the Fund’s investments and therefore the value of the Fund’s shares. To the extent that the Fund invests more of its assets in one Affiliated Fund than in another, the Fund will have greater exposure to the risks of that Affiliated Fund.

Investments in Money Market Instruments.The Fund is permitted to invest its free cash balances in money market instruments to provide liquidity or for defensive purposes. The Fund may invest in money market instruments by investing in Class E shares of Oppenheimer Institutional Government Money Market Fund (“IGMMF”), which is an Affiliated Fund. IGMMF is regulated as a money market fund under the 1940 Act, as amended. The Fund may also invest in money market instruments directly or in other affiliated or unaffiliated money market funds.

Equity Security Risk.Stocks and other equity securities fluctuate in price. The value of the Fund’s portfolio may be affected by changes in the equity markets generally. Equity markets may experience significant short-term volatility and may fall sharply at times. Different markets may behave differently from each other and U.S. equity markets may move in the opposite direction from one or more foreign stock markets. Adverse events in any part of the equity or fixed-income markets may have unexpected negative effects on other market segments.

The prices of individual equity securities generally do not all move in the same direction at the same time and a variety of factors can affect the price of a particular company’s securities. These factors may include, but are not limited to, poor earnings reports, a loss of customers, litigation against the company, general unfavorable performance of the company’s sector or industry, or changes in government regulations affecting the company or its industry.

5. Market Risk Factors

The Fund’s investments in securities and/or financial derivatives may expose the Fund to various market risk factors:

Commodity Risk. Commodity risk relates to the change in value of commodities or commodity indexes as they relate to increases or decreases in the commodities market. Commodities are physical assets that have tangible properties. Examples of these types of assets are crude oil, heating oil, metals, livestock, and agricultural products.

39       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

5. Market Risk Factors (Continued)

Credit Risk.Credit risk relates to the ability of the issuer of debt to meet interest and principal payments, or both, as they come due. In general, lower-grade, higher-yield debt securities are subject to credit risk to a greater extent than lower-yield, higher-quality securities.

Equity Risk. Equity risk relates to the change in value of equity securities as they relate to increases or decreases in the general market.

Foreign Exchange Rate Risk. Foreign exchange rate risk relates to the change in the U.S. dollar value of a security held that is denominated in a foreign currency. The U.S. dollar value of a foreign currency denominated security will decrease as the dollar appreciates against the currency, while the U.S. dollar value will increase as the dollar depreciates against the currency.

Interest Rate Risk.Interest rate risk refers to the fluctuations in value of fixed-income securities resulting from the inverse relationship between price and yield. For example, an increase in general interest rates will tend to reduce the market value of already issued fixed-income investments, and a decline in general interest rates will tend to increase their value. In addition, debt securities with longer maturities, which tend to have higher yields, are subject to potentially greater fluctuations in value from changes in interest rates than obligations with shorter maturities.

Volatility Risk.Volatility risk refers to the magnitude of the movement, but not the direction of the movement, in a financial instrument’s price over a defined time period. Large increases or decreases in a financial instrument’s price over a relative time period typically indicate greater volatility risk, while small increases or decreases in its price typically indicate lower volatility risk.

6. Shares of Beneficial Interest

The Fund has authorized an unlimited number of no par value shares of beneficial interest of each class. Transactions in shares of beneficial interest were as follows:

	Six Months Ended		February 28, 2019		Year Ended		August 31, 2018
	Shares		Amount		Shares		Amount
Class A
Sold1		8,752,334	$	347,015,058		21,273,170	$	932,056,792
Dividends and/or distributions reinvested		298,774		12,007,718		416,997		17,622,285
Redeemed		(17,709,305)		(699,099,011)		(49,132,728)		(2,142,802,381)
Net decrease		(8,658,197)	$	(340,076,235)		(27,442,561)	$	(1,193,123,304)
Class B
Sold		—	$	—		254	$	10,465
Dividends and/or distributions reinvested		—		—		—		—
Redeemed1		—		—		(468,709)		(19,657,520)
Net decrease		—	$	—		(468,455)	$	(19,647,055)

40       OPPENHEIMER DEVELOPING MARKETS FUND

6. Shares of Beneficial Interest (Continued)

	Six Months Ended		February 28, 2019		Year Ended		August 31, 2018
	Shares		Amount		Shares		Amount
Class C
Sold		234,849	$	8,592,957		710,658	$	29,007,061
Dividends and/or distributions reinvested		—		—		—		—
Redeemed		(2,312,573)		(85,460,751)		(4,659,226)		(189,868,739)
Net decrease		(2,077,724)	$	(76,867,794)		(3,948,568)	$	(160,861,678)
Class I
Sold		73,799,607	$	2,876,961,642		115,693,371	$	4,997,186,819
Dividends and/or distributions reinvested		2,119,945		83,865,017		1,705,746		71,010,204
Redeemed		(46,169,440)		(1,793,628,422)		(62,345,405)		(2,690,943,886)
Net increase		29,750,112	$	1,167,198,237		55,053,712	$	2,377,253,137
Class R
Sold		768,135	$	29,224,965		2,098,902	$	88,414,402
Dividends and/or distributions reinvested		—		—		17,434		708,333
Redeemed		(2,493,147)		(95,131,976)		(4,686,871)		(196,469,156)
Net decrease		(1,725,012)	$	(65,907,011)		(2,570,535)	$	(107,346,421)
Class Y
Sold		78,826,182	$	3,072,517,592		114,443,327	$	4,936,574,257
Dividends and/or distributions reinvested		2,291,204		90,685,856		2,294,025		95,523,194
Redeemed		(70,476,531)		(2,735,803,377)		(112,216,228)		(4,844,091,046)
Net increase		10,640,855	$	427,400,071		4,521,124	$	188,006,405

1. All outstanding Class B shares converted to Class A shares on June 1, 2018.

7. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IGMMF, for the reporting period were as follows:

	Purchases		Sales
Investment securities	$	5,747,253,992	$	4,371,000,354

8. Fees and Other Transactions with Affiliates

Management Fees.Under the investment advisory agreement, the Fund pays the Manager a management fee based on the daily net assets of the Fund at an annual rate as shown in the following table:

41       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

8. Fees and Other Transactions with Affiliates (Continued)

Fee Schedule
Up to $250 million	1.00%
Next $250 million	0.95
Next $500 million	0.90
Next $6 billion	0.85
Next $3 billion	0.80
Next $20 billion	0.75
Next $15 billion	0.74
Over $45 billion	0.73

The Manager also provides investment management related services to the Subsidiary. The Subsidiary pays the Manager a monthly management fee at an annual rate according to the above schedule. The Subsidiary also pays certain other expenses including custody and directors’ fees.

The Fund’s effective management fee for the reporting period was 0.77% of average annual net assets before any Subsidiary management fees or any applicable waivers.

Sub-Adviser Fees.The Manager has retained theSub-Adviser to provide theday-to-day portfolio management of the Fund and the Subsidiary. Under theSub-Advisory Agreement, the Manager pays theSub-Adviser an annual fee in monthly installments, equal to a percentage of the investment management fee collected by the Manager from the Fund and the Subsidiary, which shall be calculated after any investment management fee waivers. The fee paid to theSub-Adviser is paid by the Manager, not by the Fund.

Transfer Agent Fees.OFI Global (the “Transfer Agent”) serves as the transfer and shareholder servicing agent for the Fund. The Fund pays the Transfer Agent a fee based on annual net assets, which shall be calculated after any applicable fee waivers. Fees incurred and average net assets for each class with respect to these services are detailed in the Consolidated Statement of Operations and Consolidated Financial Highlights, respectively.

Sub-Transfer Agent Fees.The Transfer Agent has retained Shareholder Services, Inc., a wholly-owned subsidiary of OFI (the“Sub-Transfer Agent”), to provide theday-to-day transfer agent and shareholder servicing of the Fund. Under theSub-Transfer Agency Agreement, the Transfer Agent pays theSub-Transfer Agent an annual fee in monthly installments, equal to a percentage of the transfer agent fee collected by the Transfer Agent from the Fund, which shall be calculated after any applicable fee waivers. The fee paid to theSub-Transfer Agent is paid by the Transfer Agent, not by the Fund.

Trustees’ Compensation.The Fund has adopted an unfunded retirement plan (the “Plan”) for the Fund’s Independent Trustees. Benefits are based on years of service and fees paid to each Trustee during their period of service. The Plan was frozen with respect to adding new participants effective December 31, 2006 (the “Freeze Date”) and existing Plan Participants as of the Freeze Date will continue to receive accrued benefits under the Plan. Active Independent Trustees as of the Freeze Date have each elected a distribution method with

42       OPPENHEIMER DEVELOPING MARKETS FUND

8. Fees and Other Transactions with Affiliates (Continued)

respect to their benefits under the Plan.

During the reporting period, the Fund’s projected benefit obligations, payments to retired Trustees and accumulated liability were as follows:

Projected Benefit Obligations Increased	$	—
Payments Made to Retired Trustees		46,125
Accumulated Liability as of February 28, 2019		336,506

The Fund’s Board of Trustees (“Board”) has adopted a compensation deferral plan for Independent Trustees that enables Trustees to elect to defer receipt of all or a portion of the annual compensation they are entitled to receive from the Fund. For purposes of determining the amount owed to the Trustee under the plan, deferred amounts are treated as though equal dollar amounts had been invested in shares of the Fund or in other Oppenheimer funds selected by the Trustee. The Fund purchases shares of the funds selected for deferral by the Trustee in amounts equal to his or her deemed investment, resulting in a Fund asset equal to the deferred compensation liability. Such assets are included as a component of “Other” within the asset section of the Consolidated Statement of Assets and Liabilities. Deferral of Trustees’ fees under the plan will not affect the net assets of the Fund and will not materially affect the Fund’s assets, liabilities or net investment income per share. Amounts will be deferred until distributed in accordance with the compensation deferral plan.

Distribution and Service Plan(12b-1) Fees.Under its General Distributor’s Agreement with the Fund, OppenheimerFunds Distributor, Inc. (the “Distributor”) acts as the Fund’s principal underwriter in the continuous public offering of the Fund’s classes of shares.

Service Plan for Class A Shares. The Fund has adopted a Service Plan (the “Plan”) for Class A shares pursuant to Rule12b-1 under the 1940 Act. Under the Plan, the Fund reimburses the Distributor for a portion of its costs incurred for services provided to accounts that hold Class A shares. Reimbursement is made periodically at an annual rate of up to 0.25% of the daily net assets of Class A shares of the Fund. The Distributor currently uses all of those fees to pay dealers, brokers, banks and other financial institutions periodically for providing personal service and maintenance of accounts of their customers that hold Class A shares. Any unreimbursed expenses the Distributor incurs with respect to Class A shares in any fiscal year cannot be recovered in subsequent periods. Fees incurred by the Fund under the Plan are detailed in the Consolidated Statement of Operations.

Distribution and Service Plans for Class C and Class R Shares. The Fund has adopted Distribution and Service Plans (the “Plans”) for Class C and Class R shares, pursuant to Rule12b-1 under the 1940 Act to compensate the Distributor for distributing those share classes, maintaining accounts and providing shareholder services. Under the Plans, the Fund pays the Distributor an annual asset-based sales charge of 0.75% on Class C shares’ daily net assets and 0.25% on Class R shares’ daily net assets. The Fund also pays a service fee under the

43       OPPENHEIMER DEVELOPING MARKETS FUND

NOTES TO

CONSOLIDATED FINANCIAL STATEMENTSUnaudited / Continued

8. Fees and Other Transactions with Affiliates (Continued)

Plans at an annual rate of 0.25% of daily net assets. The Plans continue in effect from year to year only if the Fund’s Board of Trustees votes annually to approve their continuance at an in person meeting called for that purpose. Fees incurred by the Fund under the Plans are detailed in the Consolidated Statement of Operations.

Sales Charges.Front-end sales charges and CDSC do not represent expenses of the Fund. They are deducted from the proceeds of sales of Fund shares prior to investment or from redemption proceeds prior to remittance, as applicable. The sales charges retained by the Distributor from the sale of shares and the CDSC retained by the Distributor on the redemption of shares is shown in the following table for the period indicated.

Six Months Ended	Class A Front-End Sales Charges Retained by Distributor		Class A Contingent Deferred Sales Charges Retained by Distributor		Class C Contingent Deferred Sales Charges Retained by Distributor		Class R Contingent Deferred Sales Charges Retained by Distributor
February 28, 2019		$47,141		$8,515		$4,657		$—

Waivers and Reimbursements of Expenses.The Manager will waive fees and/or reimburse Fund expenses in an amount equal to the indirect management fees incurred through the Fund’s investment in IGMMF. During the reporting period, the Manager waived fees and/or reimbursed the Fund $513,616 for IGMMF management fees.

9. Borrowings and Other Financing

Joint Credit Facility.A number of mutual funds managed by the Manager participate in a $1.95 billion revolving credit facility (the “Facility”) intended to provide short-term financing, if necessary, subject to certain restrictions in connection with atypical redemption activity. Expenses and fees related to the Facility are paid by the participating funds and are disclosed separately or as other expenses on the Consolidated Statement of Operations. The Fund did not utilize the Facility during the reporting period.

10. Pending Acquisition

On October 18, 2018, Massachusetts Mutual Life Insurance Company, an indirect corporate parent of theSub-Adviser and the Manager, announced that it has entered into an agreement whereby Invesco Ltd. (“Invesco”), a global investment management company, will acquire theSub-Adviser (the “Transaction”). In connection with the Transaction, on January 11, 2019, the Fund’s Board unanimously approved an Agreement and Plan of Reorganization (the “Agreement”), which provides for the transfer of the assets and liabilities of the Fund to a corresponding, newly formed fund (the “Acquiring Fund”) in the Invesco family of funds (the “Reorganization”) in exchange for shares of the corresponding Acquiring Fund of equal value to the value of the shares of the Fund as of the close of business on the closing date. Although the Acquiring Fund will be managed by Invesco Advisers, Inc., the Acquiring Fund will, as

44       OPPENHEIMER DEVELOPING MARKETS FUND

10. Pending Acquisition (Continued)

of the closing date, have the same investment objective and substantially similar principal investment strategies and risks as the Fund. After the Reorganization, Invesco Advisers, Inc. will be the investment adviser to the Acquiring Fund, and the Fund will be liquidated and dissolved under applicable law and terminate its registration under the Investment Company Act of 1940, as amended. The Reorganization is expected to be atax-free reorganization for U.S. federal income tax purposes.

The Reorganization is subject to the approval of shareholders of the Fund. Shareholders of record of the Fund on January 14, 2019 will be entitled to vote on the Reorganization and will receive a combined prospectus and proxy statement describing the Reorganization, the shareholder meeting, and a discussion of the factors the Fund’s Board considered in approving the Agreement. The combined prospectus and proxy statement is expected to be distributed to shareholders of record on or about February 28, 2019. The anticipated date of the shareholder meeting is on or about April 12, 2019.

If shareholders approve the Agreement and certain other closing conditions are satisfied or waived, the Reorganization is expected to close during the second quarter of 2019, or as soon as practicable thereafter. This is subject to change.

45       OPPENHEIMER DEVELOPING MARKETS FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY ANDSUB-ADVISORY AGREEMENTSUnaudited

The Fund has entered into an investment advisory agreement with OFI Global Asset Management, Inc. (“OFI Global” or the “Adviser”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the“Sub-Adviser”) (“OFI Global” and “OFI” together the “Managers”) and OFI Global has entered into asub-advisory agreement with OFI whereby OFI provides investmentsub-advisory services to the Fund (collectively, the “Agreements”).Each year, the Board of Trustees (the “Board”), including a majority of the independent Trustees, is required to determine whether to approve the terms of the Agreements and the renewal thereof. The Investment Company Act of 1940, as amended, requires that the Board request and evaluate, and that the Managers provide, such information as may be reasonably necessary to evaluate the terms of the Agreements. The Board employs an independent consultant to prepare a report that provides information, including comparative information that the Board requests for that purpose. In addition toin-person meetings focused on this evaluation, the Board receives information throughout the year regarding Fund services, fees, expenses and performance.

The Managers and the independent consultant provided information to the Board on the following factors: (i) the nature, quality and extent of the Managers’ services, (ii) the comparative investment performance of the Fund and the Managers, (iii) the fees and expenses of the Fund, including comparative fee and expense information, (iv) the profitability of the Managers and their affiliates, including an analysis of the cost of providing services, (v) whether economies of scale are realized as the Fund grows and whether fee levels reflect these economies of scale for Fund investors and (vi) other benefits to the Managers from their relationship with the Fund. The Board was aware that there are alternatives to retaining the Managers.

Outlined below is a summary of the principal information considered by the Board as well as the Board’s conclusions.

Nature, Quality and Extent of Services. The Board considered information about the nature, quality and extent of the services provided to the Fund and information regarding the Managers’ key personnel who provide such services. The Managers’ duties include providing the Fund with the services of theSub-Adviser’s portfolio manager and investment team, who provide research, analysis and other advisory services in regard to the Fund’s investments; and securities trading services. OFI Global is responsible for oversight of third-party service providers; monitoring compliance with applicable Fund policies and procedures and adherence to the Fund’s investment restrictions; risk management; and oversight of theSub-Adviser. OFI Global is also responsible for providing certain administrative services to the Fund. Those services include providing and supervising all administrative and clerical personnel who are necessary in order to provide effective corporate administration for the Fund; compiling and maintaining records with respect to the Fund’s operations; preparing and filing reports required by the U.S. Securities and Exchange Commission; preparing periodic reports regarding the operations of the Fund for its shareholders; preparing proxy materials for shareholder meetings; and preparing the registration statements required by federal and state securities laws for the sale of the Fund’s shares. OFI Global also provides the Fund with office space, facilities and equipment.

46       OPPENHEIMER DEVELOPING MARKETS FUND

The Board also considered the quality of the services provided and the quality of the Managers’ resources that are available to the Fund. The Board took account of the fact that theSub-Adviser has over fifty years of experience as an investment adviser and that its assets under management rank it among the top mutual fund managers in the United States. The Board evaluated the Managers’ advisory, administrative, accounting, legal, compliance and risk management services, among other services, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of their staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Justin Leverenz the portfolio manager for the Fund, and theSub-Adviser’s investment team and analysts. The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which the Board members have become knowledgeable about through their experiences with the Managers and in connection with the review or renewal of the Fund’s service agreements or service providers. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreements.

Investment Performance of the Managers and the Fund. Throughout the year, the Managers provided information on the investment performance of the Fund, the Adviser and theSub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Managers and by the independent consultant, comparing the Fund’s historical performance to relevant benchmarks or market indices and to the performance of other retail funds in the diversified emerging markets category. The Board noted that the Fund’sone-year and three-year performance was below its category median although its five-year andten-year performance was better than its category median.

Fees and Expenses of the Fund. The Board reviewed the fees paid to the Adviser and the other expenses borne by the Fund. The Board noted that the Adviser, not the Fund, pays theSub-Adviser’s fee under thesub-advisory agreement. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retailfront-end load diversified emerging markets funds with comparable asset levels and distribution features. The Board noted that the Fund’s contractual management fee and total expenses were lower than its peer group and category median.

Economies of Scale and Profits Realized by the Managers. The Board considered information regarding the Managers’ costs in serving as the Fund’s investment adviser andsub-adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund. The Board noted that the Fund currently has management fee breakpoints, which are intended to share with Fund shareholders economies of scale that may exist as the Fund’s assets grow.

47       OPPENHEIMER DEVELOPING MARKETS FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY ANDSUB-ADVISORY AGREEMENTSUnaudited / Continued

Other Benefits to the Managers. In addition to considering the profits realized by the Managers, the Board considered information that was provided regarding the direct and indirect benefits the Managers receive as a result of their relationship with the Fund, including compensation paid to the Managers’ affiliates and research provided to the Adviser in connection with permissible brokerage arrangements (soft dollar arrangements).

Conclusions. These factors were also considered by the independent Trustees meeting separately from the full Board, assisted by experienced counsel to the Fund and to the independent Trustees. Fund counsel and the independent Trustees’ counsel are independent of the Managers within the meaning and intent of the Securities and Exchange Commission Rules.

Based on its review of the information it received and its evaluations described above, the Board, including a majority of the independent Trustees, decided to continue the Agreements through September 30, 2019. In arriving at its decision, the Board did not identify any factor or factors as being more important than others, but considered all of the above information, and considered the terms and conditions of the Agreements, including the management fees, in light of all the surrounding circumstances.

48       OPPENHEIMER DEVELOPING MARKETS FUND

PORTFOLIO PROXY VOTING POLICIES AND GUIDELINES; UPDATES TO STATEMENT OF INVESTMENTSUnaudited

The Fund has adopted Portfolio Proxy Voting Policies and Guidelines under which the Fund votes proxies relating to securities (“portfolio proxies”) held by the Fund. A description of the Fund’s Portfolio Proxy Voting Policies and Guidelines is available (i) without charge, upon request, by calling the Fund toll-free at 1.800.CALL OPP (225.5677), (ii) on the Fund’s website at www.oppenheimerfunds.com, and (iii) on the SEC’s website at www.sec.gov. In addition, the Fund is required to file FormN-PX, with its complete proxy voting record for the 12 months ended June 30th, no later than August 31st of each year. The Fund’s voting record is available (i) without charge, upon request, by calling the Fund toll-free at 1.800.CALL OPP (225.5677), and (ii) in the FormN-PX filing on the SEC’s website at www.sec.gov.

The Fund files its complete schedule of portfolio holdings with the SEC for the first quarter and the third quarter of each fiscal year on FormN-Q. The Fund’s FormN-Q filings are available on the SEC’s website at www.sec.gov. Beginning in April 2019, the Fund will no longer file FormN-Qs and will instead disclose its portfolio holdings monthly on FormN-PORT, which will also be available on the SEC’s website at www.sec.gov.

Householding—Delivery of Shareholder Documents

This is to inform you about OppenheimerFunds’ “householding” policy. If more than one member of your household maintains an account in a particular fund, OppenheimerFunds will mail only one copy of the fund’s prospectus (or, if available, the fund’s summary prospectus), annual and semiannual report and privacy policy. The consolidation of these mailings, called householding, benefits your fund through reduced mailing expense, and benefits you by reducing the volume of mail you receive from OppenheimerFunds. Householding does not affect the delivery of your account statements.

Please note that we will continue to household these mailings for as long as you remain an OppenheimerFunds shareholder, unless you request otherwise. If you prefer to receive multiple copies of these materials, please call us at1.800.CALL-OPP(225-5677).You may also notify us in writing or via email. We will begin sending you individual copies of the prospectus (or, if available, the summary prospectus), reports and privacy policy within 30 days of receiving your request to stop householding.

49       OPPENHEIMER DEVELOPING MARKETS FUND

OPPENHEIMER DEVELOPING MARKETS FUND

Trustees and Officers	Joel W. Motley, Chairman of the Board of Trustees and Trustee
	Beth Ann Brown, Trustee
	Edmund P. Giambastiani, Jr., Trustee
	Elizabeth Krentzman, Trustee
	Mary F. Miller, Trustee
	Joanne Pace, Trustee
	Daniel Vandivort, Trustee
	Brian F. Wruble, Trustee
	Justin Leverenz, Vice President
	Arthur P. Steinmetz, Trustee, President and Principal Executive Officer
	Cynthia Lo Bessette, Secretary and Chief Legal Officer
	Jennifer Foxson, Vice President and Chief Business Officer
	Mary Ann Picciotto, Chief Compliance Officer and Chief Anti-Money
	Laundering Officer
	Brian S. Petersen, Treasurer and Principal Financial & Accounting Officer
Manager	OFI Global Asset Management, Inc.
Sub-Adviser	OppenheimerFunds, Inc.
Distributor	OppenheimerFunds Distributor, Inc.
Transfer and Shareholder	OFI Global Asset Management, Inc.
Servicing Agent
Sub-Transfer Agent	Shareholder Services, Inc.
	DBA OppenheimerFunds Services
Independent Registered	KPMG LLP
Public Accounting Firm
Legal Counsel	Kramer Levin Naftalis & Frankel LLP
	The financial statements included herein have been taken from the records of the Fund without examination of those records by the independent registered public accounting firm.

© 2019 OppenheimerFunds, Inc. All rights reserved.

50       OPPENHEIMER DEVELOPING MARKETS FUND

PRIVACY NOTICE

As an Oppenheimer fund shareholder, you are entitled to know how we protect your personal information and how we limit its disclosure.

Information Sources

We obtainnon-public personal information about our shareholders from the following sources:

● Applications or other forms.

● When you create a user ID and password for online account access.

● When you enroll in eDocs Direct, SM our electronic document delivery service.

● Your transactions with us, our affiliates or others.

● Technologies on our website, including: “cookies” and web beacons, which are used to collect data on the pages you visit and the features you use.

If you visit oppenheimerfunds.com and do not log on to the secure account information areas, we do not obtain any personal information about you. When you do log on to a secure area, we do obtain your user ID and password to identify you. We also use this information to provide you with products and services you have requested, to inform you about products and services that you may be interested in and assist you in other ways.

We do not collect personal information through our website unless you willingly provide it to us, either directly by email or in those areas of the website that request information. In order to update your personal information (including your mailing address, email address and phone number) you must first log on and visit your user profile.

If you have set your browser to warn you before accepting cookies, you will receive the warning message with each cookie. You can refuse cookies by turning them off in your browser. However, doing so may limit your access to certain sections of our website.

We use cookies to help us improve and manage our website. For example, cookies help us recognize new versus repeat visitors to the site, track the pages visited, and enable some special features on the website. This data helps us provide better service for our website visitors.

Protection of Information

We do not disclose anynon-public personal information (such as names on a customer list) about current or former customers to anyone, except as permitted by law.

Disclosure of Information

Copies of confirmations, account statements and other documents reporting activity in your fund accounts are made available to your financial advisor (as designated by you). We may also use details about you and your investments to help us, our financial service affiliates, or firms that jointly market their financial products and services with ours, to better serve your investment needs or suggest educational material that may be of interest to you. If this requires us to provide you with an opportunity to “opt in” or “opt out” of such information sharing with a firm not affiliated with us, you will receive notification on how to do so, before any such sharing takes place.

Right of Refusal

We will not disclose your personal information to unaffiliated third parties (except as permitted by law), unless we first offer you a reasonable opportunity to refuse or “opt out” of such disclosure.

51       OPPENHEIMER DEVELOPING MARKETS FUND

PRIVACY NOTICE Continued

Internet Security and Encryption

In general, the email services provided by our website are encrypted and provide a secure and private means of communication with us. To protect your own privacy, confidential and/ or personal information should only be communicated via email when you are advised that you are using a secure website.

As a security measure, we do not include personal or account information innon-secure emails, and we advise you not to send such information to us innon-secure emails. Instead, you may take advantage of the secure features of our website to encrypt your email correspondence. To do this, you will need to use a browser that supports Secure Sockets Layer (SSL) protocol.

● All transactions conducted via our websites, including redemptions, exchanges and purchases, are secured by the highest encryption standards available. SSL is used to establish a secure connection between your PC and OppenheimerFunds’ server. It transmits information in an encrypted and scrambled format.

● Encryption is achieved through an electronic scrambling technology that uses a “key” to code and then decode the data. Encryption acts like the cable converter box you may have on your television set. It scrambles data with a secret code so that no one can make sense of it while it is being transmitted. When the data reaches its destination, the same software unscrambles the data.

● You can exit the secure area by closing your browser or, for added security, you can use the Log Out button before you close your browser.

Other Security Measures

We maintain physical, electronic and procedural safeguards to protect your personal account information. Our employees and agents have access to that information only so that they may offer you products or provide services, for example, when responding to your account questions.

How You Can Help

You can also do your part to keep your account information private and to prevent unauthorized transactions. If you obtain a user ID and password for your account, safeguard that information. Strengthening your online credentials–your online security profile–typically your user name, password, and security questions and answers, can be one of your most important lines of defense on the Internet. For additional information on how you can help prevent identity theft, visit https://www. oppenheimerfunds.com/security.

Who We Are

This joint notice describes the privacy policies of the Oppenheimer funds, OppenheimerFunds, Inc., each of its investment adviser subsidiaries, OppenheimerFunds Distributor, Inc. and OFI Global Trust Co. It applies to all Oppenheimer fund accounts you presently have, or may open in the future, using your Social Security number—whether or not you remain a shareholder of our funds. This notice was last updated as of November 2017. In the event it is updated or changed, we will post an updated notice on our website at oppenheimerfunds.com. If you have any questions about this privacy policy, email us by clicking on theContact Us section of our website at oppenheimerfunds.com, write to us at P.O. Box 5270, Denver, CO 80217-5270, or call us at800 CALL OPP (225 5677).

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OppenheimerFunds^®

The Right Way

to Invest

Visit us at oppenheimerfunds.com for24-hr access to

account information and transactions or call us at 800.CALL

OPP (800.225.5677) for24-hr automated information and

automated transactions. Representatives also available

Mon–Fri8am-8pm ET.

Visit Us oppenheimerfunds.com Call Us 800 225 5677
Follow Us	Oppenheimer funds are distributed by OppenheimerFunds Distributor, Inc. 225 Liberty Street, New York, NY 10281-1008 © 2019 OppenheimerFunds Distributor, Inc. All rights reserved. RS0785.001.0219 April 24, 2019

Item 2. Code of Ethics.

Not applicable to semiannual reports.

Item 3. Audit Committee Financial Expert.

Not applicable to semiannual reports.

Item 4. Principal Accountant Fees and Services.

Not applicable to semiannual reports.

Item 5. Audit Committee of Listed Registrants

Not applicable.

Item 6. Schedule of Investments.

a) Not applicable. The complete schedule of investments is included in Item 1 of this FormN-CSR.

b) Not applicable.

Item 7. Disclosure of Proxy Voting Policies and Procedures forClosed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers ofClosed-End Management Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities byClosed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

The Fund’s Governance Committee Provisions with Respect to Nominations of Directors/Trustees to the Respective Boards

None

Item 11. Controls and Procedures.

Based on their evaluation of the registrant’s disclosure controls and procedures (as defined in rule30a-3(c) under the Investment Company Act of 1940 (17 CFR270.30a-3(c)) as of 2/28/2019, the registrant’s principal executive officer and principal financial officer found the registrant’s disclosure controls and procedures to provide reasonable assurances that information required to be disclosed by the registrant in the reports that it files under the Securities Exchange Act of 1934 (a) is accumulated and communicated to registrant’s management, including its principal executive officer and principal financial officer, to allow timely decisions regarding required disclosure, and (b) is recorded, processed, summarized and reported, within the time

periods specified in the rules and forms adopted by the U.S. Securities and Exchange Commission.

There have been no changes in the registrant’s internal controls over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Disclosure of Securities Lending Activities forClosed-End Management Investment Companies.

Not applicable.

Item 13. Exhibits.

(a)	(1) Exhibit attached hereto.
	(2) Exhibits attached hereto.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Oppenheimer Developing Markets Fund

By:	/s/ Arthur P. Steinmetz
	Arthur P. Steinmetz
	Principal Executive Officer
Date:	4/19/2019

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By:	/s/ Arthur P. Steinmetz
	Arthur P. Steinmetz
	Principal Executive Officer
Date:	4/19/2019

By:	/s/ Brian S. Petersen
	Brian S. Petersen
	Principal Financial Officer
Date:	4/19/2019