Exhibit EX-99

99.1

Announcement on 2017/05/19: UMC will attend investor conferences on 2017/05/24

99.2

Announcement on 2017/05/19: Represent subsidiary United Semiconductor (Xiamen) Co., Ltd.to announce related materials on acquisition of machinery and equipment

99.3

Announcement on 2017/05/22: To announce related materials on acquisition of machinery and equipment

99.5

Announcement on 2017/05/09: the trading and pledge of UMC common shares by directors, executive officers and 10% shareholders of UMC

1. Date of the investor conference: 2017/05/24
2. Time of the investor conference: 09:00 AM
3. Location of the investor conference: Grand Hyatt Hotel, Taipei
4. Brief information disclosed in the investor conference: The Company will attend the “Taiwan Executive Forum”, held by HSBC.
5. The presentation of the investor conference release: It will be the same as the investor conference on 2017/04/26.
6. Will the presentation be released in the Company’s website: Yes, please refer to the Company’s website at www.umc.com
7. Any other matters that need to be specified: None.

Represent subsidiary United Semiconductor (Xiamen) Co., Ltd.to announce related materials on
acquisition of machinery and equipment

1. Name and nature of the subject matter (e.g. land located at Sublot XX, Lot XX, North District, Taichung City): Machinery and equipment
2. Date of the occurrence of the event: 2017/03/07~2017/05/19
3. Transaction volume (e.g. XX square meters, equivalent to XX p’ing), unit price, total transaction price:
Transaction volume: one batch;
Average unit price: NT$539,139,898;
Total transaction price: NT$539,139,898
4. Counterparty to the trade and its relationship with the company (if the trading counterpart is a natural person and is not an actual related party of the Company, the name of the trading counterpart is not required to be disclosed): LAM RESEARCH INTERNATIONAL SARL; Non-related party transaction
5. Where the counterpart to the trade is an actual related party, a public announcement shall also include the reason for choosing the related party as trading counterpart and the identity of the previous owner (including its relationship with the company and the trading counterpart), price of transfer and the date of acquisition: Not applicable
6. Where a person who owned the property within the past five years has been an actual related person of the company, a public announcement shall also include the dates and prices of acquisition and disposal by the related person and the person’s relationship to the company at those times: Not applicable
7. Anticipated loss or profit from the disposal (not applicable in cases of acquisition of assets) (where originally deferred, the status or recognition shall be stated and explained): Not applicable
8. Terms of delivery or payment (including payment period and monetary amount), restrictive covenants in the contract, and other important stipulations: Base on purchase order payment term.
9. The manner of deciding on this transaction (such as tender invitation, price comparison, or price negotiation), the reference basis for the decision on price and the decision-making department:
Transaction: price negotiation;
The reference basis for the decision on price: market price;
The decision-making department: the Selection Meeting
10. Name of the professional appraisal institution and its appraisal amount: Not applicable
11. Reason for any significant discrepancy with the transaction amount, and opinion of the certifying CPA: Not applicable
12. Is the appraisal report price a limited price or specific price? : Not applicable
13. Has an appraisal report not yet been obtained? : Not applicable
14. Reason for an appraisal report not been obtained: Not applicable
15. Broker and broker’s fee: None
16. Concrete purpose or use of the acquisition or disposal: For production
17. Do the directors have any objection to the present transaction? : Not applicable
18. Any other matters that need to be specified: None

1. Name and nature of the subject matter (e.g. land located a Sublot XX, Lot XX, North District, Taichung City): Machinery and equipment
2. Date of the occurrence of the event: 2016/08/22~2017/05/22
3. Transaction volume (e.g. XX square meters, equivalent to XX p’ing), unit price, total transaction price:
Transaction volume: one batch;
Average unit price: $503,660,766 NTD;
Total transaction price: $503,660,766 NTD
4. Counterparty to the trade and its relationship with the company (if the trading counterpart is a natural person and is not an actual related party of the Company, the name of the trading counterpart is not required to be disclosed): TOKYO ELECTRON LIMITED; non-related party transaction
5. Where the counterpart to the trade is an actual related party, a public announcement shall also include the reason for choosing the related party as trading counterpart and the identity of the previous owner (including its relationship with the company and the trading counterpart), price of transfer and the date of acquisition: Not applicable
6. Where a person who owned the property within the past five years has been an actual related person of the company, a public announcement shall also include the dates and prices of acquisition and disposal by the related person and the person’s relationship to the company at those times: Not applicable
7. Anticipated loss or profit from the disposal (not applicable in cases of acquisition of assets) (where originally deferred, the status or recognition shall be stated and explained): Not applicable
8. Terms of delivery or payment (including payment period and monetary amount), restrictive covenants in the contract, and other important stipulations: Base on purchase order payment term.
9. The manner of deciding on this transaction (such as tender invitation, price comparison, or price negotiation), the reference basis for the decision on price and the decision-making department:
Transaction: price negotiation;
The reference basis for the decision on price: market price;
The decision-making department: the Selection Meeting
10. Name of the professional appraisal institution and its appraisal amount: Not applicable
11. Reason for any significant discrepancy with the transaction amount, and opinion of the certifying CPA: Not applicable
12. Is the appraisal report price a limited price or specific price? : Not applicable
13. Has an appraisal report not yet been obtained? : Not applicable
14. Reason for an appraisal report not been obtained: Not applicable
15. Broker and broker’s fee: None
16. Concrete purpose or use of the acquisition or disposal: For production
17. Do the directors have any objection to the present transaction? : Not applicable
18. Any other matters that need to be specified: None

This is to report the changes or status of 1) Sales volume, 2) Funds lent to other parties, 3) Endorsements and guarantees, and 4) Financial derivative transactions for the period of April 2017.

Last Month

This Month

(actual amount

Balance as of period end

(actual amount provided)

provided)

Limit of lending

UMC

3,977,160

3,994,320

21,573,376

Note : On December 14, 2016, the board of directors resolved to lend funds to USC(Xiamen) for the amount up to US$132 million. The actual amount lent to USC(Xiamen) as of April 30, 2017 was US$60 million.


	This Month		Last Month
Balance as of period end	(actual amount provided)		(actual amount provided)		Limit of lending
UMC (Note1)		1,700,000		1,700,000		43,146,752
UMC (Note2)		9,340,300		9,380,600		43,146,752
UMC (Note3)		18,239	—			43,146,752
Note1 : On December 24, 2014, the board of directors resolved to provide endorsement to Nexpower’s syndicated loan from banks including Bank of Taiwan for the amount up to NT$ 1,700 million. Note2 : On February 22, 2017, the board of directors resolved to provide endorsement to USC(Xiamen) ‘s syndicated loan from banks for the amount up to US$310 million. Note3 : On April 26, 2017, the board of directors resolved to provide endorsement to SocialNex Italia 1 s.r.l. ‘s VAT guarantee to Italian Tax Office for the amount up to EUR$ 558 thousand.


Financial instruments	Forwards		IRS
Deposit Paid		0		0
Royalty Income (Paid)		0		0
Unwritten-off Trading Contracts		2,350,140		0
Fair Value		24,723		0
Net Profit from Fair Value		85,034		0
Written-off Trading Contracts		15,399,962		0
Realized profit (loss)		275,433		0

This is to report 1) the trading of directors, executive officers and 10% shareholders of United Microelectronics Corporation (“UMC”) (NYSE: UMC); 2) the pledge and clear of pledge of UMC common shares by directors, executive officers and 10% shareholders of UMC;

The pledge and clear of pledge of UMC common shares by directors, executive officers and 10% shareholders:


Period	Items	2017		2016		Changes		%
April	Net sales		11,926,270		10,764,403		1,161,867		10.79	%
Year-to-Date	Net sales		49,344,220		45,168,482		4,175,738		9.24	%


Title	Name	Number of shares as of March 31, 2017	Number of shares as of April 30, 2017		Changes

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