When do mutual fund prices get updated?

i.e. stock prices are updated when the market closes (around 4:00 pm est). when do prices for mutual funds get updated (what time of day)?

It depends upon the fund. Some price hourly, however 99% of firms price their funds at the close of business. When they release the information is specific to the firm and when it appears is specific to the data provider. You should presume that any price you see was the close of business the prior day, unless you specifically know otherwise. Since funds are not designed to daytrade and since funds have strange redemption rules based upon the phrasing of the Investment Company Act, it doesn't matter much because you are pretty much required to sell or buy blind.

If I buy at noon tomorrow, it will be at the next official price, which is usually close of business and will happen on the following day. So if the price tonight is 10.13, the real but undisclosed price tomorrow at noon is 10.12 but finishes at 10.14, then I will pay 10.14 the day after tomorrow at the opening of business probably but at some point in the day.

Closed end funds only update once per week, usually on Fridays.

Mutual fund prices are available in two NASDAQ feeds. The first feed used by Yahoo and most other services contains about 5% errors and missing prices and is available about 17:15 Eastern time.

In 2001, NASDAQ introduced a second reporting session from 18:20 to 19:00 Eastern for fund companies to provide late price updates to the electronic media carrying fund data.

Of the major retail fund price distributors only Investors FastTrack holds for the second feed which averages 2% errors and missing data. Additionally, http://www.fasttrack.net hand corrects and provides a proprietary morning feed to thousands subscribers. This feed reduces errors to under 0.3%

Each one is a little different, but normally for US funds it is about 9:00 PM or so, Eastern Time. I know that it is not like stocks, that get updated by the second. Normally, because they own a lot of stocks and securities, etc., it takes them a while to determine what their new value is. This is especially true if they have foreign holdings.