I was reading the ISO 10962(classification of financial instruments, 2015 version) and I found that the investment on Collective Investment Vehicles (Standard Funds, Hedge Funds, REIT, ETF, Pension Funds, Fund of Funds and Private Equity Funds according with the ISO classification) could give to the investor shares or units, but it wasn't precise about the difference between them. I was reading wikipedia, investopedia but none of those clarify the difference.

What is the difference? How can I tell which term applies to my investments?

Regarding the commentary of @DStanley it seems like there is a difference, because the fourth atrribute of every one of them is Security Type and the possibilities are:

- Shares

- Shares for QI

- Units

- Units for QI

  • The difference is in how the investment is structured, and sometimes in whether investors get a vote in how the investment is run.
    – keshlam
    Commented Feb 7, 2017 at 13:30
  • So what is the actual question? Are you not certain when to use Shares and when to use Units?
    – D Stanley
    Commented Feb 7, 2017 at 19:22
  • @DStanley yes that's the actual question, if you tell me how differentiate one from another that would be fine.
    – rlartiga
    Commented Feb 7, 2017 at 19:24

2 Answers 2


There are some nuances based on the actual investment vehicle, but they are similar concepts. They both represent a portion of entitlement, whether ownership, dividends, voting rights, etc.

An an example, Master Limited Partnerships (MLPs) have limited partners that purchase "units", which entitle them to a portion of the MLPs periodic cash flows, but do not convey any ownership or rights (the Managing Partners in the MLP are responsible for the operations of the entity). The portion is determined by the number of units owned relative to all units outstanding. Prices are often quoted "per unit" instead of "per share".

Looking at ISO-10962, I do not think there is any significant difference between the terms - if there is a specific section of the standard that you think needs disambiguation, then you can add that to your question, but for all practical purpose they represent the same concept.

  • Also I made a mistake the ISO is the 10962. Anyway your answer is fine. I just want to clarify the difference
    – rlartiga
    Commented Feb 7, 2017 at 17:28
  • I accepted your question. Please could you chage the part of "the iso-15022"
    – rlartiga
    Commented Feb 14, 2017 at 20:30

I can say they are similar concepts for all practical purposes. They are similar in the aspect of being simply a unit of counting.

Ishares, one of the most prominent issuers of ETF's sets a unit to equal 50000 shares. According to the prospectus of SPY ETF, only authorized market participants such as investment banks are allowed to participate in Creation and Distribution transaction directly with the fund, and these operations must be in block-size Units of 50000 shares or multiples thereof

You can read the prospectus at https://www.ishares.com/us/library/stream-document?stream=reg&product=I-SP500&shareClass=NA&documentId=925833~926358~926348~925661~925593&iframeUrlOverride=%2Fus%2Fliterature%2Fprospectus%2Fp-ishares-core-s-and-p-500-etf-3-31.pdf

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