July 23 (Reuters) - U.S. homebuilder PulteGroup ( PHM )

beat Wall Street estimates for second-quarter profit on Tuesday,

as an acute shortage of existing houses drove up demand for new

constructions.

Shares of the company gained about 1% in premarket trading

after its home sales revenue also rose during the period.

With the popular 30-year fixed mortgage rate hovering at

about 7% for months, U.S. homeowners are holding onto lower

rates secured on properties during an era of cheap debt.

This "rate lock-in" has constrained sales of existing homes

in the United States, prompting buyers to turn to newly

constructed houses even amid a surge in property prices.

"While interest-rate movements can impact short-term

homebuying demand, long-term market dynamics continue to benefit

from a structural shortage of homes caused by years of

underbuilding," said CEO Ryan Marshall.

PulteGroup ( PHM ), which usually sells a mix of cheaper

pre-constructed homes and more expensive build-to-order homes

based on buyer specifications, delivered 8,097 homes in the

quarter ended June 30, up 8% from a year earlier.

The Atlanta, Georgia-based company reported a 10% rise in

home sales revenue to $4.4 billion in the second quarter.

Average selling price of $549,000 per home was also 2%

higher than the year earlier, with home sales gross margin

rising 30 basis points to about 30%.

The company earned an adjusted $3.77 per share in the second

quarter, ahead of analysts' average estimate of $3.27 per share,

according to LSEG data.