Master Limited Partnerships

ETRACS Wells Fargo MLP Index

The ETRACS Wells Fargo MLP Index due October 29, 2040 is designed to track an investment in the Wells Fargo^® Master Limited Partnership Index (the "Index"), and pays a variable quarterly coupon linked to the cash distributions associated with the underlying MLP constituents, less investor fees. The Index is a float adjusted, capitalization weighted Index that seeks to measure the performance of all energy master limited partnerships ("MLP") listed on the New York Stock Exchange ("NYSE") or NASDAQ that satisfy market capitalization (at least $200 million at the time of inclusion) and other eligibility requirements.

The Index was created in December 2006 and has no performance history prior to that date.

Market data
Distributions
Returns

Sector weightings
Index comparisons
Risks & Benefits

Product profile

Product Name	ETRACS Wells Fargo MLP Index
Underlying Index	Wells Fargo^® Master Limited Partnership Index
Issuer	UBS AG
Current Annual Index Yield*	5.79%
Ticker Symbol	MLPW
CUSIP	902664 408
Primary Exchange	NYSE Arca
Initial Trade Date	October 29, 2010
Maturity Date	October 29, 2040
Annual Tracking Fee (%)*	0.85% per annum accrued on a daily basis

*As of December 31, 2010. See "Key benefits & Selected risks" as well as the "Important legal information specific to ETRACS ETNs" link below for more information.

The Current Annual Index Yield is calculated by Wells Fargo and is determined by taking the most recently declared distribution of each of the Master Limited Partnerships that constitute the Index (“constituent MLP”), and creating an annualized yield for each constituent MLP by (i) multiplying that number by the dividend frequency and (ii) dividing the resulting number by the current market price of the applicable constituent MLP. The Current Annual Index Yield is the sum of the products of those individual yields of each constituent MLP and their relative weights in the Index. You are not guaranteed any coupon or distribution amount under the ETN.

Market data

Closing Price	27.28	Volume	1,500
Net Change	0.00	20 Day Volume Average	2,742.55
% Change	0.00	Shares Outstanding	700,000
High (52 week)	29.22	Market Cap	19,096,000.67
Low (52 week)	22.22	Daily Indicative Value	27.08
Updated on: May 15, 2012

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Distributions

	Amount per security	Ex-date	Record date	Payable
Q1 2011	$0.1290	01/10/2011	01/12/2011	01/21/2011
Q2 2011	$0.3222	04/08/2011	04/12/2011	04/20/2011
Q3 2011	TBD	07/12/2011	07/14/2011	07/22/2011
Q4 2011	TBD	10/11/2011	10/13/2011	10/21/2011

Source: UBS, NYSE and Bloomberg.

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Historical returns

	Total return*	Annualized return*	3 Month	1 Year	5 Years
Wells Fargo^® Master Limited Partnership Index	66.59%	13.40%	8.78%	37.26%	13.60%
S&P 500^® Index	-2.83%	-0.70%	10.27%	15.06%	-0.83%
S&P 500 Utilities^® Index	0.39%	0.10%	0.44%	5.46%	0.01%
Dow Jones-UBS Commodity Index^SM	2.59%	0.63%	16.76%	16.83%	0.96%

*Since inception

Historical results for the period from December 11, 2006 through December 31, 2010.

Source: Bloomberg, Standard & Poor’s, and Dow Jones

Historical information presented is as of December 31, 2010 and is furnished as a matter of information only. Historical performance of the Underlying Index is not an indication of future performance. Future performance of the Index may differ significantly from historical performance, either positively or negatively.

The ETRACS ETNs are subject to investor fees. As a result, the return on the ETNs will always be lower than the total return on a direct investment in the Index or the Index constituents.

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Top 10 Sector weightings

Name	Ticker	Weight
Enterprise Product Partners LP	EPD	13.24%
Kinder Morgan Energy Part LP	KMP	10.00%
Plains All American Pipeline LP	PAA	5.63%
Energy Transfer Partners LP	ETP	5.41%
Magellan Midstream Partners	MMP	4.31%
Linn Energy LLC	LINE	3.71%
Kinder Morgan Management LLC	KMR	3.60%
Energy Transfer Equity LP	ETE	3.59%
Enbridge Energy Partners LP	EEP	2.96%
Buckeye Partners LP	BPL	2.48%

Source: Wells Fargo as of October 25, 2010

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Total Return Index Comparison

Index comparisons graph

The graph above illustrates the historical returns of the Index from December 11, 2006 through December 31, 2010 in comparison with other benchmark indices.

For each time period presented, the total return of the Index is the price return of the Index during such period, but also incorporating distributions made by each Index constituent during such period into the value of the Index. While the Coupon Amount of the ETNs, if any, will reflect the cash distributions that a hypothetical holder of the Underlying Index constituents would be entitled to receive during the relevant period, any Coupon Amount will be reduced by the Annual Tracking Fee. The graph above does not account for the fee. As a result, the return on the ETNs will always be lower than the total returns on a direct investment in the Index constituents.

Historical performance of the Index is not an indication of future performance. Future performance of the Index may differ significantly from historical performance, either positively or negatively

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Key Benefits & Selected risk considerations

Benefits:

Exposure to a portfolio of energy MLPs through a single investment.
Income via variable quarterly coupons linked to the cash distributions, if any, paid on the MLPs in the Underlying Index, less investor fees. If the MLPs do not make distributions or those distributions do not overcome the Investor Fees, then Investors will not receive any coupons.
Tax administration - While significant aspects of the tax treatment of the ETNs is uncertain, the coupons associated with the ETN are reported as ordinary income on Form 1099, and therefore the administrative burden associated with K-1 forms is eliminated.

Selected risk considerations:

An investment in the ETRACS ETNs involves risks. Selected risks are summarized here, but we urge you to read the more detailed explanation of risks described under "Risk Factors" beginning on page S-18 in the prospectus supplement for the ETRACS ETNs (the "ETRACS Prospectus"). Capitalized terms used below but not defined herein shall have the meanings attributed to them in the ETRACS Prospectus.

You may lose some or all of your investment — The ETRACS ETNs are fully exposed to any decline in the level of the Index, and will also be subject to the upfront fee. If the increase in the level of the Index, as compared to the Initial Index Level, is insufficient to offset the negative effect of the Annual Tracking Fee and Redemption Fee Amount, if applicable, less any Coupon Amounts, any Stub Reference Distribution Amount and/or Adjusted Coupon Amount, as applicable, or if the Final Index Level is less than the Initial Index Level, you will lose some or all of your investment at maturity or call, or upon early redemption. In addition, the ETRACS ETNs are also subject to an upfront fee that you pay as part of the issue price.
Payment based on the arithmetic mean of closing levels – The payment on the ETRACS ETNs at maturity or call will be based on the arithmetic mean of the closing levels of the Index over a number of days during the final measurement period or call measurement period, and not on the closing level of the Index on a single day, as specified in the ETRACS Prospectus. The arithmetic mean of the closing levels of the Index over a number of days will most likely differ from the closing level of the Index on a single day.
Negative effect of the upfront fee — ETRACS ETNs may be sold to the public at prices up to 102% of their Issuance Amount. The "upfront fee" is the increase in price over the stated Principal Amount, or Issuance Amount, as applicable. Because the payment at maturity or call, or upon early redemption, will be calculated on the basis of the Principal Amount and not the issue price, the upfront fee represents an immediate cost to you and will not grow along with any increase in the level of the Index, as compared to the Initial Index Level.
Market risk — The return on the ETRACS ETNs, which may be positive or negative, is linked to the return on the Index as measured by the Index Performance Ratio, and which, in turn, is affected by a variety of market and economic factors, interest rates in the markets and economic, financial, political, regulatory, judicial or other events that affect the Index constituents or the markets generally.
Limited performance history – The return on the ETRACS ETNs is linked to the performance of the Index, which was introduced in December 2006. As a result, the Index has a limited performance history, and it is uncertain how the index will perform. Limited historical information will be available for you to consider in making an independent investigation of the Index performance, which may make it more difficult for you to make an informed decision with respect to an investment in the ETRACS ETNs than if the Index had a longer performance history.
Credit of UBS — The ETRACS ETNs are senior unsecured debt obligations of the issuer, UBS, and are not, either directly or indirectly, an obligation of or guaranteed by any third party. Any payment to be made on the ETRACS ETNs, including any payment at maturity, call or upon early redemption, depends on the ability of UBS to satisfy its obligations as they come due. As a result, the actual and perceived creditworthiness of UBS will affect the market value, if any, of the ETRACS ETNs prior to maturity, call or early redemption. In addition, in the event UBS were to default on its obligations, you may not receive any amounts owed to you under the terms of the ETRACS ETNs.
Concentration in a particular industry — There is only one industry – energy – related to the MLPs included in the Index. An investment in the ETRACS ETNs will increase your portfolio's exposure to fluctuations in the energy industry.
A trading market for the ETRACS ETNs may not develop — Although the ETRACS ETNs are listed on NYSE Arca, a trading market for the ETRACS ETNs may not develop. Certain affiliates of UBS may engage in limited purchase and resale transactions in the ETRACS ETNs, although they are not required to and may stop at any time. We are not required to maintain any listing of the ETRACS ETNs on NYSE Arca or any other exchange. Therefore, the liquidity of the ETRACS ETNs may be limited.
Minimum redemption amount — You must elect to redeem at least 50,000 ETRACS ETNs for UBS to repurchase your ETRACS ETNs, unless we determine otherwise or your broker or other financial intermediary bundles your ETRACS ETNs for redemption with those of other investors to reach this minimum requirement and there can be no assurance that they can or will do so. Therefore, the liquidity of the ETRACS ETNs may be limited.
You are not guaranteed a coupon payment — You will not receive a coupon payment on a Coupon Payment Date if the Reference Distribution Amount is less than the Accrued Tracking Fee (which is based on the Annual Tracking Fee). Similarly, you will not receive a coupon payment on a Redemption Date or Call Settlement Date if the Adjusted Reference Distribution Amount is less than the Adjusted Tracking Fee (which is based on the Annual Tracking Fee) and, as applicable, the Redemption Fee Amount.
Uncertain tax treatment — Significant aspects of the tax treatment of the ETRACS ETNs are uncertain. You should consult your own tax advisor about your own tax situation.
UBS's call right — UBS may elect to redeem all outstanding ETRACS ETNs at any time on any Exchange Business Day (or if such day is not an Exchange Business Day, the next Exchange Business Day) on or after November 3, 2011, as described under "Specific Terms of the Securities — UBS's Call Right" beginning on page S-46 of the ETRACS Prospectus. If UBS exercises its Call Right, the Call Settlement Amount may be less than the Principal Amount of your ETRACS ETNs. Alternatively, if the ETRACS ETNs have increased in value, you may have to invest your proceeds in a lower-return investment.

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