United's shares were valued at 15.16 US dollars (£9.26) when the market opened for trading on Monday - well down on a high point last May of 19.34 (£11.82) but higher than the 12-month low of 14.39 (£8.79).
In overall terms that can be seen as a drop in the value of £250million but sources say the Glazer family who own United take a long-term view about the value of the shares, which were launched in August 2012 in New York at a price of 14 dollars.
One United source said: "The Glazer family take very much a long-term view about share prices and the value of the club - there have been a number of fluctuations in the last 18 months but they remain comfortable about the current position."
In the last year there have been numerous ups and downs - the announcement by Sir Alex Ferguson last May that he was retiring led to a sharp drop in share price.
The price recovered over the summer but there was another fall in October, only for promising financial figures from the club for the first quarter to prompt a recovery, and then another swift fall in December.
United's comparatively poor form on the pitch this season - they are by no means assured of a place in the Champions League - may be a cause for concern for some investors, but in financial terms the club is expected to post record revenues this season.
The Glazers are also understood to be determined to have patience with Ferguson's successor David Moyes, understanding that he will need time to settle in after taking over from the most successful manager the game has ever seen.
Moyes was given a six-year contract in the summer - a statement of intent by the owners that they view him as well as the club as a long-term investment.
Some analysts believe United have been over-valued anyway despite the club's fan-base and income.
Other stock market watchers believe that the expected announcement of a new kit deal with Nike will send the share value rocketing again.