"The opportunities that we see going forward and the excitement that they [the Glazers] have in this is undiminished," Ed Woodward told reporters on Tuesday.
While the club had attracted potential suitors, "I do not see them selling completely for many, many years," he said.
Some fans have criticised the Glazers - father Malcolm and his six children, saying they loaded the 19-times English champions with too much debt when buying it for 790 million pounds in 2005.
United listed in New York in August under a dual-share structure that left the Glazers firmly in control.
The shares, issued at $14 to value the club at $2.3 billion, were down 1.1 percent on the day at $12.25 at 16:15 GMT.
Woodward said he was confident about the club's business model - it claims to be the world's most popular team with 659 million followers - and was not worried about the share price.
FERGUSON BACKED WITH CASH
The club now had gross debt of around 360 million pounds, Woodward said, adding it was comfortable with interest payments of around 31 million pounds this year on its own forecast for underlying earnings (EBITDA) of at least 107 million pounds.
That meant manager Sir Alex Ferguson could compete with major European clubs in the transfer market. "Every single player that Sir Alex has wanted to buy, he has been supported by the owners. The money has been there to back him," Woodward said.
United, which signed Dutch international striker Robin van Persie from Arsenal this summer for an estimated 22 million pounds, are second in the 20-team Premier League.
That has silenced some criticism after the team failed to win a trophy last season for the first time 2005. To add to fans' pain, United lost the Premier League title to local rivals Manchester City, bankrolled by cash from Abu Dhabi.
Football's financial landscape is about to change, with clubs facing exclusion from major European competitions as early as 2014/15 unless they curb losses.
Woodward said United were supportive of "Financial Fair Play" measures that could rein in spending by clubs such as City or Qatari-owned Paris Saint-Germain. "I am hearing everyone is taking it seriously and working towards it."
United plans to open an office on the U.S east coast to tap into a "really big opportunity" as interest in football grows across the Atlantic, he said.
