UMC Reports First Quarter 2014 Results

Contacts: Bowen Huang / David Wong UMC, Investor Relations + 886-2-2658-9168, ext. 16957 bowen_huang@umc.com david_wong@umc.com UMC Reports First Quarter 2014 Results 1Q Results Top Guidance on Better than Expected Demand, Momentum Continues into 2Q First Quarter 2014 Overview 1 : Revenue: NT$31.69 billion (US$1.04 billion) Gross margin: 18.6%; operating margin: 3.0% Foundry capacity utilization rate: 81% Net income attributable to the stockholders of the parent: NT$1.18 billion (US$38.7 million) Earnings per share: NT$0.09; earnings per ADS: US$0.015 Taipei, Taiwan, ROC April 30, 2014 United Microelectronics Corporation (NYSE: UMC; TWSE: 2303) ( UMC or The Company ), a leading global semiconductor foundry, today announced its consolidated operating results for the first quarter of 2014. Revenue was NT$31.69 billion, with gross margin at 18.6% and operating margin at 3.0%. Net income attributable to the stockholders of the parent was NT$1.18 billion, with earnings per ordinary share of NT$0.09. Mr. Po-Wen Yen, CEO of UMC, said In the first quarter of 2014, UMC recorded NT$28.71 billion in revenue from the foundry segment, with operating margin from foundry operations of 4.0%. Wafer shipments reached 1.258 million 8-inch equivalent wafers. CEO Yen added, In a seasonally quiet quarter, UMC's first quarter of 2014 foundry performance exceeded guidance, driven by continuous chip demand that brought overall capacity utilization to 1 Unless otherwise stated, all financial figures discussed in this announcement are prepared in accordance with TIFRSs recognized by Financial Supervisory Commission in the ROC, which is different from IFRSs issued by the International Accounting Standards Board. They represent comparisons among the three-month period ending Mar 31, 2014, the three-month period ending Dec 31, 2013, and the equivalent three-month period that ended Mar 31, 2013. For all 1Q14 results, New Taiwan Dollar (NT$) amounts have been converted into U.S. Dollars at the Mar 31, 2014 exchange rate of NT$ 30.463 per U.S. Dollar. Page 1 of 12

81%. Growth was led by the computing sector. As a result, contribution from 65nm and below technologies represented 51% of sales, including 20% from 40nm. For 28nm, our communication and consumer customers continue to be encouraged by our sustained yield improvement. While the average 28nm yields have shown stable performance, the continuous rise in our peak wafer yields will be a convincing factor for customers to enter pilot production in the coming months. UMC also continues to focus on capturing fast growing opportunities and further expanding our market share in China. Recently, UMC hosted its 2014 China Technology Forum in Shanghai to demonstrate our manufacturing excellence and comprehensive coverage of semiconductor applications. With 20 years of pure-play foundry experience, our technology leadership in logic and specialty solutions will help us gain additional design-wins in the Chinese fabless industry. CEO Yen continued, For the second quarter of 2014, UMC will benefit from the continued growth in customer demand, especially from the communication segment. We expect increased wafer shipments and higher capacity utilization rates to drive better profitability. At the leading-edge, 40nm demand continues to show strength while 28nm business is gaining momentum. We are confident that our engineering team s steady progress in 28nm yield enhancement activities will help UMC to capture key business and achieve strategic goals in the near future. We will continue to execute and take the necessary steps to propel our future growth. In the long run, we will further strengthen our technology solutions and service quality to enhance shareholder returns. Page 2 of 12

Summary of Operating Results Operating Results (Amount: NT$ million) 1Q14 4Q13 QoQ % change 1Q13 YoY % change Net Operating Revenues 31,694 30,719 3.2 27,781 14.1 Gross Profit 5,901 5,557 6.2 4,492 31.4 Operating Expenses (5,016) (5,317) (5.7) (4,178) 20.1 Net Other Operating Income and Expenses 56 (46) - (20) - Operating Income 941 194 385.1 294 220.1 Net Non-Operating Income and Expenses 351 889 (60.5) 7,249 (95.2) Net Income Attributable to the Stockholders of the Parent 1,180 749 57.5 6,593 (82.1) EPS (NT$ per share) 0.09 0.06 0.52 (US$ per ADS 2 ) 0.015 0.010 0.085 Revenue increased 3.2% QoQ to NT$31.69 billion from NT$30.72 billion in 4Q13, and increased 14.1% YoY from NT$27.78 billion in 1Q13. Gross profit was NT$5.90 billion, or 18.6% of revenue, compared to NT$5.56 billion, or 18.1% of 4Q13 revenue. Operating income for the quarter was NT$0.94 billion, or 3.0% of revenue, compared to operating income of NT$0.19 billion, or 0.6% of 4Q13 revenue. Net income attributable to the stockholders of the parent in 1Q14 was NT$1.18 billion, compared to NT$749 million in 4Q13. Earnings per ordinary share for the quarter were NT$0.09. Earnings per ADS were US$0.015. The basic weighted average number of outstanding shares in 1Q14 was 12,479,924,736, compared with 12,476,082,332 shares in 4Q13 and 12,631,240,995 shares in 1Q13. The diluted weighted average number of outstanding shares was 13,157,984,032 in 1Q14, compared with 13,243,379,446 shares in 4Q13 and 13,396,609,065 shares in 1Q13. The fully diluted share count on March 31, 2014 was approximately 13,333,286,000. On March 31, 2014, UMC held 200 million treasury shares acquired from the 15th share buy-back program. 2 One ADS represents five Taiwan-listed ordinary shares. Page 3 of 12

Detailed Financials Section The rise in revenue was largely due to an increase in shipments during 1Q14. Depreciation slightly increased 2.6% to NT$8.15 billion. Gross profit climbed 6.2% to NT$5.90 billion, or 18.6% of revenue. Total operating expenses decreased 5.7% to NT$5.02 billion. Sales and marketing expenses decreased 8.1% to NT$833 million, mainly due to lower mask expenses. Research and development expenses decreased to NT$3.34 billion, mostly due to a temporary reduction in engineering wafer use. COGS & Expenses (Amount: NT$ million) 1Q14 4Q13 QoQ % change 1Q13 YoY % change Net Operating Revenues 31,694 30,719 3.2 27,781 14.1 COGS (25,793) (25,162) 2.5 (23,289) 10.8 Depreciation (8,145) (7,939) 2.6 (7,628) 6.8 Other Mfg. Costs (17,648) (17,223) 2.5 (15,661) 12.7 Gross Profit 5,901 5,557 6.2 4,492 31.4 Gross Margin (%) 18.6% 18.1% 16.2% Operating Expenses (5,016) (5,317) (5.7) (4,178) 20.1 G&A (848) (826) 2.7 (1,019) (16.8) Sales & Marketing (833) (906) (8.1) (763) 9.2 R&D (3,335) (3,585) (7.0) (2,396) 39.2 Net Other Operating Income & Expenses 56 (46) - (20) - Operating Income 941 194 385.1 294 220.1 Net non-operating income in 1Q14 was NT$351 million. Net investment loss was NT$110 million, mainly from impairment charges from financial assets. Gain on disposal of investments was NT$367 million, primarily from the sale of financial assets. Non-Operating Income and Expenses (Amount: NT$ million) 1Q14 4Q13 1Q13 Non-Operating Income and Expenses 351 889 7,249 Net Interest Income and Expenses (23) (53) (82) Net Investment Gain and Loss (110) (394) 12 Gain and Loss on Disposal of Investment 367 985 33 Exchange Gain and Loss 22 114 37 Other Gain and Loss 95 237 7,249 Page 4 of 12

Cash inflow from operations was NT$6.23 billion. CAPEX spending was NT$6.28 billion, including NT$6.22 billion from the foundry segment. As a result free cash flow was negative NT$45 million in 1Q14. Cash flow from financing activities increased to NT$2.40 billion, mostly due to the increase of NT$2.33 billion in short- term bank loans. Total cash inflow was NT$3.08 billion in 1Q14. Over the next 12 months, the company expects to repay NT$3.20 billion in bank loans. Cash Flow Summary (Amount: NT$ million) For the 3-Month Period Ended Mar. 31, 2014 For the 3-Month Period Ended Dec. 31, 2013 Cash Flow from Operating Activities 6,232 10,806 Net Income before tax 1,292 1,083 Depreciation & Amortization 9,850 9,568 Changes in Working Capital (4,746) 658 Other (164) (503) Cash Flow from Investing Activities (6,100) (7,738) Capital Expenditures (6,277) (7,751) Other 177 13 Cash Flow from Financing Activities 2,395 (2,787) Bank Loans 2,325 (842) Redemption of Bonds (57) (1,971) Other 127 26 Effect of Exchange Rate Changes on Cash and Cash Equivalents 573 215 Net Increase in Cash and Cash Equivalents Cash and Cash Equivalents of Disposal Group included in Non-Current Assets Held for Sale Total increase in Cash and Cash Equivalents 3,100 496 (16) - 3,084 496 Cash and cash equivalents increased to NT$53.92 billion, largely due to the increase in short-term bank loans. Days of inventory decreased by one day to 50 days in 1Q14. Current Assets (Amount: NT$ billion) 1Q14 4Q13 1Q13 Cash and Cash Equivalents 53.92 50.83 50.58 Notes & Accounts Receivable 18.89 16.82 17.44 Days Sales Outstanding 51 53 55 Inventories, net 14.42 13.99 14.23 Days of Inventory 50 51 53 Total Current Assets 96.75 88.80 91.80 Current liabilities increased to NT$49.24 billion, mostly due to the increase in short-term bank loans. Debt to equity ratio remained unchanged at 39%. Liabilities (Amount: NT$ billion) 1Q14 4Q13 1Q13 Total Current Liabilities 49.24 48.20 37.30 Notes & Accounts Payable 7.15 7.41 6.63 Short-Term Credit / Bonds 24.42 21.19 11.23 Payables on Equipment 4.82 6.70 5.74 Other 12.85 12.90 13.70 Long-Term Credit / Bonds 27.66 28.42 41.55 Total Liabilities 83.85 83.46 86.02 Debt to Equity 39% 39% 40% Page 5 of 12

Analysis of Revenue 3 for Foundry Segment Revenue from Asia Pacific region increased to 45%, reflecting the strength in Asia-Pacific-based communication and consumer customers. Revenue Breakdown by Region Region 1Q14 4Q13 3Q13 2Q13 1Q13 North America 45% 47% 43% 47% 44% Asia Pacific 45% 41% 44% 42% 46% Europe 7% 8% 7% 8% 9% Japan 3% 4% 6% 3% 1% Revenue from 65nm and advanced technologies represented 51% in 1Q14, including 20% from 40nm. Revenue Breakdown by Geometry Geometry 1Q14 4Q13 3Q13 2Q13 1Q13 40nm and below 20% 24% 20% 20% 18% 40nm<x<=65nm 31% 29% 34% 31% 32% 65nm<x<=90nm 7% 7% 6% 6% 6% 90nm<x<=0.13um 14% 14% 16% 15% 14% 0.13um<x<=0.18um 12% 12% 11% 13% 15% 0.18um<x<=0.35um 12% 11% 10% 11% 11% 0.5um and above 4% 3% 3% 4% 4% The percentage of revenue from fabless customers increased to 92%. Revenue Breakdown by Customer Type Customer Type 1Q14 4Q13 3Q13 2Q13 1Q13 Fabless 92% 89% 86% 90% 90% IDM 8% 11% 14% 10% 10% The percentage of revenue from the computer segment increased to 18%, reflecting demand strength from PC-related areas such as LCD controllers. Revenue Breakdown by Application (1) Application 1Q14 4Q13 3Q13 2Q13 1Q13 Computer 18% 15% 16% 18% 22% Communication 46% 49% 52% 51% 47% Consumer 31% 31% 28% 28% 28% Others 5% 5% 4% 3% 3% (1) Computer consists of ICs such as CPU, GPU, HDD controllers, DVD/CD-RW control ICs, PC chipset, audio codec, keyboard controller, monitor scaler, USB, I/O chipset. Communication consists of handset components, broadband, WLAN, bluetooth, Ethernet, LAN, DSP, etc. Consumer consists of ICs used for DVD players, DTV, STB, MP3/MP4, flash controller, game consoles, DSC, smart cards, toys, etc. 3 Revenue in this section represents wafer sales Page 6 of 12

Blended ASP Trend for Foundry Segment Blended average selling price (ASP) during 1Q14 decreased slightly. Unit: USD 1,500 1,000 500 0 1Q13 2Q13 3Q13 4Q13 1Q14 Shipment and Utilization Rate 4 for Foundry Segment Wafer shipments increased 1.8% sequentially to 1,258K in 1Q14, compared to 1,236K 8-inch equivalent wafers in 4Q13. Overall utilization rate improved to 81%. Wafer Shipments (8 K equivalents) Wafer Shipments 1Q14 4Q13 3Q13 2Q13 1Q13 1,258 1,236 1,329 1,307 1,125 Quarterly Capacity Utilization Rate 1Q14 4Q13 3Q13 2Q13 1Q13 Utilization Rate 81% 79% 87% 85% 78% Total Capacity (8 K equivalents) 1,563 1,560 1,548 1,537 1,461 4 Utilization Rate = Quarterly Wafer Out / Quarterly Capacity Page 7 of 12

Capacity 5 for Foundry Segment Capacity during the first quarter was 1,563K 8-inch equivalent wafers. The incremental increase in capacity was due to the advance node capacity expansion at Fab 12A. The estimated installed capacity for the second quarter of 2014 will be 1,597K 8-inch equivalent wafers, due to the capacity expansion mainly from Fab 8N and advanced node expansion at 12 facilities. Annual Capacity in thousands of wafers Geometry FAB (um) Quarterly Capacity in thousands of wafers 2013 2012 2011 2010 FAB 2Q14E 1Q14 4Q13 3Q13 Fab6A 6" 3.5 0.45 448 481 538 588 Fab6A 113 111 113 113 Fab8A 8" 0.5 0.25 813 815 813 816 Fab8A 204 201 204 204 Fab8C 8" 0.35 0.11 347 360 359 366 Fab8C 87 86 87 87 Fab8D 8" 0.13 0.09 382 371 364 314 Fab8D 93 94 96 96 Fab8E 8" 0.5 0.18 418 449 469 410 Fab8E 105 103 105 105 Fab8F 8" 0.18 0.11 388 389 388 388 Fab8F 98 96 98 98 Fab8S 8" 0.18 0.11 335 348 307 304 Fab8S 84 83 84 84 Fab8N 8" 0.5 0.13 469 - - - Fab8N 140 126 128 128 Fab12A 12" 0.18 0.028 651 579 501 374 Fab12A 174 171 164 164 Fab12i 12" 0.13 0.040 550 537 530 454 Fab12i 147 145 145 139 Total (1) 6,107 5,514 5,322 4,791 Total 1,597 1,563 1,560 1,548 YoY Growth Rate 11% 4% 11% 4% 2010~2012 figures account for UMC parent company only. (1) One 6-inch wafer is converted into 0.5625(6 2 /8 2 ) 8-inch equivalent wafer; one 12-inch wafer is converted into 2.25(12 2 /8 2 ) 8-inch equivalent wafers. Capacity total figures are expressed in 8-inch equivalent wafers. CAPEX for Foundry Segment The foundry capital expenditure for 2014 remains unchanged at US$1.1~1.3 billion. UMC spent US$207 million in the first quarter. Capital Expenditure by Year - in US$ billion Year 2013 2012 2011 2010 2009 CAPEX $ 1.1 $ 1.7 $ 1.6 $ 1.8 $ 0.55 2009~2012 figures account for UMC parent company only. 2014 CAPEX Plan 8" 12" Total 11% 89% US$1.1~1.3 billion 5 Estimated capacity numbers are based on calculated maximum output rather than designed capacity. The actual capacity numbers may differ depending upon equipment delivery schedules, pace of migration to more advanced process technologies, and other factors affecting production ramp-up. Page 8 of 12

Second Quarter of 2014 Outlook & Guidance Quarter-over-Quarter Guidance: Foundry Segment Wafer Shipments: To increase by low-teens percentage range Foundry Segment ASP in US$: To remain flat Foundry Segment Profitability: Gross profit margin will be in the mid-20 percentage range Foundry Segment Capacity Utilization: High-80% range 2014 CAPEX for Foundry Segment: US$1.1bn to US$1.3bn Guidance to New Business Segment: Revenue to be approximately NT$3bn and operating loss to be approximately NT$0.45bn Recent Developments / Announcements Apr. 22, 2014 UMC Files Form 20-F for 2013 with US Securities and Exchange Commission Apr. 18, 2014 UMC Holds 2014 China Technology Forum Apr. 16, 2014 UMC Board of Directors Announces Amendment to the Proposal of Cash Distribution for its Annual Shareholders Meeting - Total cash distribution to shareholders amounts to NT$6,253 million including NT$0.49/share from additional paid-in capital plus NT$0.01/share from earnings Mar. 12, 2014 UMC Board of Directors Announces Proposals for its Annual Shareholders Meeting - Shareholder cash dividend of NT$6,249 million - Employee cash bonus of NT$1,163 million - Approved the proposal of private placement plan in the 2014 Annual General Meeting. The amount proposed is to be no more than 10% of registered capital - The 2014 AGM will be held on June 11, 2014 at UMC s Fab 8S Conference Hall in Hsin Chu Feb. 12, 2014 Feb. 05, 2014 Jan. 27, 2014 Jan. 24, 2014 Synopsys, Realtek and UMC Collaborate on Industry s First Single-Chip Ultra High Definition Smart TV SoC UMC's Taiwan Fabs Gain MOE Cleaner Production Certification UMC Receives Best Supplier Award from Lantiq for Second Straight Year UMC 4Q 2013 Financial Results Please visit UMC s website for further details regarding the above announcements Page 9 of 12

Conference Call / Webcast Announcement Wednesday, April 30, 2014 Time: 5:00 PM (Taipei) / 5:00 AM (New York) / 10:00 AM (London) Dial-in numbers and Access Codes: USA Toll Free: 1-800 871-3110, 1-888 700-7397 Taiwan Number: 02-2192-8016 Other Areas: +886-2-2192-8016 Access Code: UMC A live webcast and replay of the 1Q14 results announcement will be available at www.umc.com under the Investors / Events section. About UMC UMC (NYSE: UMC, TWSE: 2303) is a leading global semiconductor foundry that provides advanced technology and manufacturing for applications spanning every major sector of the IC industry. UMC s robust foundry solutions allow chip designers to leverage the company s leading-edge processes, which include 28nm poly-sion and gate-last High-K/Metal Gate technology, mixed signal/rfcmos, and a wide range of specialty technologies. Production is supported through 10 wafer manufacturing facilities that include two advanced 300mm fabs; Fab 12A in Taiwan and Singapore-based Fab 12i. Fab 12A consists of Phases 1-4 which are in production for customer products down to 28nm. Construction has been completed for Phases 5&6, with future plans for Phases 7&8. The company employs over 15,000 people worldwide and has offices in Taiwan, mainland China, Europe, Japan, Korea, Singapore, and the United States. UMC can be found on the web at http://www.umc.com Note from UMC Concerning Forward-Looking Statements Some of the statements in the foregoing announcement are forward looking within the meaning of the U.S. Federal Securities laws, including statements about future outsourcing, wafer capacity, technologies, business relationships and market conditions. Investors are cautioned that actual events and results could differ materially from these statements as a result of a variety of factors, including conditions in the overall semiconductor market and economy; acceptance and demand for products from UMC; and technological and development risks. Further information regarding these and other risks is included in UMC s filings with the U.S. Securities and Exchange Commission, including its registration statements and reports on Forms F-1, F-3, F-6 and 20-F and 6-K, in each case as amended. UMC does not undertake any obligation to update any forward-looking statement as a result of new information, future events or otherwise, except as required under applicable law. Page 10 of 12

Safe Harbor Statements This release contains forward-looking statements. These statements constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and as defined in the U.S. Private Securities Litigation Reform Act of 1995. You can identify these forward-looking statements by use of words such as strategy, expects, continues, plans, anticipates, believes, will, estimates, intends, projects, goals, targets and other words of similar meaning. You can also identify them by the fact that they do not relate strictly to historical or current facts. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the actual performance, financial condition or results of operations of UMC to be materially different from what is stated or may be implied in such forward-looking statements. Investors are cautioned that actual events and results could differ materially from those statements as a result of a number of factors including, but not limited to: (i) our dependence upon the frequent introduction of new services and technologies based on the latest developments in our industry; (ii) the intensely competitive semiconductor, communications, consumer electronics and computer industries and markets; (iii) the risks associated with international global business activities; (iv) our dependence upon key personnel; (v) general economic and political conditions; (vi) possible disruptions in commercial activities caused by natural and human-induced events and disasters, including terrorist activity, armed conflict and highly contagious diseases; (vii) reduced end-user purchases relative to expectations and orders; and (viii) fluctuations in foreign currency exchange rates. Further information regarding these and other risks is included in UMC s filings with the U.S. Securities and Exchange Commission, including its registration statements and reports on Form F-1, F-3, F-6 and 20-F and 6-K, in each case as amended. UMC does not undertake any obligation to update any forward-looking statement as a result of new information, future events or otherwise, except as required under applicable law. The financial statements included in this release are prepared and published in accordance with TIFRSs recognized by Financial Supervisory Commission in the ROC, which is different from IFRSs issued by the International Accounting Standards Board. Investors are cautioned that there may be significant differences between TIFRSs and IFRSs. In addition, TIFRSs and IFRSs differ in certain significant respects from ROC GAAP and US GAAP. This presentation is not an offer of securities for sale in the United States. Securities may not be offered or sold in the United States absent registration or an exemption from registration. Any public offering of securities to be made in the United States will be made by means of a prospectus that may be obtained from the issuer or selling security holder and that will contain detailed information about the company and management, as well as financial statements. - FINANCIAL TABLES TO FOLLOW - Page 11 of 12