揭開美帝股息免收陀地之謎

首先溫故知新，海外投資者投資美帝股市，其身份多數是 nonresident alien（NRA），NRA的定義可參考（細節略過）：
Publication 519 (2016), U.S. Tax Guide for Aliens
1. Nonresident Alien or Resident Alien?
對 NRA 來說，foreign income 是不用扣稅的：

Publication 519 (2016), U.S. Tax Guide for Aliens2.   Source of Income > Nonresident Alien
A nonresident alien usually is subject to U.S. income tax only on U.S. source income. Under limited circumstances, certain foreign source income is subject to U.S. tax. See Foreign Income in chapter 4.

作為 NRA，其 U.S. income 可分為兩類：Effectively connected income（ECI）或 Non-effectively connected income（NEC），定義如下：

Publication 519 (2016), U.S. Tax Guide for Aliens
4. How Income of Aliens Is Taxed > Nonresident Aliens
A nonresident alien's income that is subject to U.S. income tax must be divided into two categories.

• Income that is effectively connected with a trade or business in the United States, and

• Income that is not effectively connected with a trade or business in the United States (discussed under The 30% Tax, later).

The difference between these two categories is that effectively connected income, after allowable deductions, is taxed at graduated rates. These are the same rates that apply to U.S. citizens and residents. Income that is not effectively connected is taxed at a flat 30% (or lower treaty) rate.

其中，NRA 的 ECI 會按美帝子民的稅法收稅，包括免稅額（例如２０１６年的個人免稅額就是4,050帝幣）及其他扣減：

Publication 519 (2016), U.S. Tax Guide for Aliens
5.   Figuring Your Tax > Exemptions > Nonresident Aliens
Generally, if you are a nonresident alien engaged in a trade or business in the United States, you can claim only one personal exemption ($4,050 for 2016).

而 NEC 則是收 flat rate 30% （或是根據美帝與該投資人所居住國家所簽訂之 tax treaty 而定）。
投資人純粹買賣股票，是不屬於 engaged in a trade or business in the United States，故此美帝股票派息便不屬於 ECI，而是 NEC：

Publication 519 (2016), U.S. Tax Guide for Aliens
4. How Income of Aliens Is Taxed > Nonresident Aliens > Trade or Business in the United States
Trading in stocks, securities, and commodities.   If your only U.S. business activity is trading in stocks, securities, or commodities (including hedging transactions) through a U.S. resident broker or other agent, you are not engaged in a trade or business in the United States.

通常，海外投資人在證券行開戶買賣美股的時候，都要填寫並簽署一份叫 W-8BEN 的表格，申明自己係 NRA，投資回報屬於 NEC，故此證券行作為 withholding agent 便可以代美帝 hold 起 30% 股息稅：

Instructions for Form W-8BEN (Rev. February 2014), Certificate of Foreign Status of Beneficial Owner forUnited States Tax Withholding and Reporting (Individuals)
General Instructions > Who Must Provide Form W-8BEN
If any of the income for which you have provided a Form W-8BEN becomes effectively connected, this is a change in circumstances and Form W-8BEN is no longer valid with respect to such income. You must file Form W-8ECI.

如果投資人某些美帝收入已轉變成 ECI，則該投資人需要填多一份 W-8ECI，二表並存：W-8BEN 管 NEC，W-8ECI 管 ECI：

Instructions for Form W-8ECI (02/2014), Certificate of Foreign Person's Claim That Income Is Effectively Connected With the Conduct of a Trade or Business in the United States
General Instructions > Purpose of Form
If you expect to receive both income that is effectively connected and income that is not effectively connected from a withholding agent, you must provide Form W-8ECI for the effectively connected income and Form W-8BEN, Form W-8BEN-E, Form W-8EXP, or Form W-8IMY (as appropriate) for income that is not effectively connected.

NEC 一般要扣 30% 稅，資本增值（capital gain）除外；這就是 30% withholding tax 的由來：

Publication 519 (2016), U.S. Tax Guide for Aliens
4. How Income of Aliens Is Taxed > Nonresident Aliens > The 30% Tax
The following gains are subject to the 30% (or lower treaty) rate without regard to the 183-day rule, discussed later.
1. Gains on the disposal of timber, coal, or domestic iron ore with a retained economic interest.
2. Gains on contingent payments received from the sale or exchange of patents, copyrights, and similar property after October 4, 1966.
3. Gains on certain transfers of all substantial rights to, or an undivided interest in, pat-ents if the transfers were made before October 5, 1966.
4. Gains on the sale or exchange of original issue discount obligations.
:
:
:
If you were in the United States for less than 183 days during the tax year, capital gains (other than gains listed earlier) are tax exempt unless they are effectively connected with a trade or business in the United States during your tax year.

去到填報稅表 1040NR，說明書也再重申了一次 ECI 和 NEC 的分別和申報辦法：

Instructions for Form 1040NR (2016), U.S. Nonresident Alien Income Tax Return
General Instructions > How To Report Income on Form 1040NR > Kinds of Income
You must divide your income for the tax year into the following three categories.

• Income effectively connected with a U.S. trade or business. This income is taxed at the same rates that apply to U.S. citizens and residents. Report this income on page 1 of Form 1040NR. Pub. 519 describes this income in greater detail.
• U.S. income not effectively connected with a U.S. trade or business. This income is taxed at 30% unless a treaty between your country of residence (as defined under the treaty) and the United States has set a lower rate that applies to you. Report this income on Schedule NEC on page 4 of Form 1040NR. Pub. 519 describes this income in greater detail.
• Income exempt from U.S. tax. If the income is exempt from tax by treaty, complete item L of Schedule OI on page 5 of Form 1040NR and line 22 on page 1.
  

綜合以上「閱讀心得」，可得出以下結論：
１. NRA 只需就 U.S. income 交稅，foreign income 是免稅的。
２. 一般而言，NRA 買賣美帝股票的投資收入 (包括資產增值及股息派發)，只能算是 U.S. income 中的 NEC。
３. 一般而言，NRA 在開戶買賣帝股時已填寫 W-8BEN，申明該等收入是 NEC，得享免資產增值稅與及 30% withholding tax 的優惠，但就不能享有美帝公民的免稅額。
４. 根據定義，NRA 是可以有 ECI 的，但就要填報 W-8ECI，該等股息收入方可以計入 gross income，再以美帝公民的個人免稅額（及／或其他免稅額）扣減，同時資產增值不能免稅，得出 net taxable income 就以美帝公民的稅率繳稅。
對於呆灣有財經博客宣稱可以將股息收入填在報稅表 1040NR 中 的 ECI 欄位，並以個人免稅額抵銷，成功申請退稅，又大搞投資報稅班教呆民填表（畢竟大部分呆民的英語能力實在太爛，並且恬不知恥地全無改進的心態，就呢一點魔術師已對呆民毫無好感）；魔術師就大感不以為然，甚至乎覺得此舉有扮傻搏大霧藉故逃稅之嫌（以該財經博客之英語能力應該足夠去理解魔術師所引述的條文）。既然股息係 NEC，便會被收取 30% withholding tax，將股息同時又當係 ECI 去申請個人免稅額在邏輯上是矛盾的，有些博客話「留返俾 IRS 決定對錯」更是語言偽術：你成功做到了，唔等於係人地有決定了什麼，人地也有可能是左手來右手去的官僚，俾你偷到雞而已。
又，呢一篇有戴頭盔提及以 ECI 申請退稅的「風險」，實在是自打嘴巴：如果是信心滿滿，合法合規的，哪怕甚麼「風險」呢？
至於為何美帝稅局 IRS 會批准退稅，魔術師不是 IRS 肚裡面條蟲仔，當然無法代答；如果係都要估，educated guess 大概都係抽樣調查抽佢地唔中、或者就算抽中咗，但要追討少量稅款人力物力划不來、罪不責眾、甚至乎可能有人已被美帝追稅，但報喜不報憂扮傻扮英文差，大概是這樣吧...
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伸延閱讀：
綠角財經筆記：2009海外券商投資報稅心得(How to File for Tax Refund with Form 1040NR)
Rib的投資學習筆記：配息超過免稅額後的報稅方法和稅務規劃——利用家人名義開戶，即可增加免稅額
尋找1042-S的故事
美帝股息免收陀地之謎