FYI: Mutual funds and Unit Investment Trusts are both investment vehicles that allow investors to own a pool of different stocks, bonds or other asset classes in one single unit.
Mutual funds seem to be the clear leader in the open-ended fund world, with more than $16 trillion in net assets as of 2016. Unit Investment Trusts (UITs) are much less popular and only have around $85 billion in net assets as of 2016. Even though both mutual funds and UITs allow investors to buy a single diversified portfolio in one investment, there are several similarities and differences between them.
Regards,
Ted
http://mutualfunds.com/education/mutual-funds-vs-unit-investment-trusts-uits/
Comments
From the SEC: "A UIT typically will make a one-time 'public offering' of only a specific, fixed number of units (like closed-end funds)."
https://www.sec.gov/fast-answers/answersuithtm.html
The major exceptions are ETFs that are structured as UITs. Since ETFs do continuously offer to buy and sell shares (albeit just to authorized participants), they can be viewed as open end funds. (I'm using a generous definition of open-end here; technically only mutual funds are open end funds; see SEC Investment Company Fast Answers.)
It is precisely this exception that highlights the next error in the intro, viz. that UITs have only $85B in net assets. The original ETF, SPY, is a UIT. It alone has $275B in assets.