By choice or by force, more and more people in South Florida’s foreclosure-ridden housing market are renting, rather than owning, their homes.

In an ironic twist on economics, that dynamic is actually helping the resale market. According to sales reports released Thursday, South Florida is on track to set a new sales record this year.

The reason: investors.

The majority of today’s homebuyers are not first-time owners or growing families, but opportunistic investors. International buyers and locals with cash are making money in the region’s distressed market by buying up foreclosed homes and turning them into rentals.

Homeowners who have been foreclosed upon, and those who either can’t or won’t buy in this economy, are flooding the rental market with unprecedented demand.

“I talk to a couple investors all over South America and they tell me they buy these condos and it takes them about a week to rent them,” said Craig Studnicky, principal of Miami real estate firm RelatedISG. “Each and every month, the rents are going up.”

Spurred by investor activity, South Florida homes sales rose again in September, according to new data by the Miami Association of Realtors. Sales were down, however, compared to last month.

There were 848 single-family home sales in Miami-Dade County in September, up 46 percent from the same month in 2010, but down 10.8 percent from August. Existing Miami-Dade condo sales reached 1,319, up 58 percent on a year-over-year basis, and flat compared to the previous month.

In Broward County, single-family home sales reached 1,079, up 11 percent year-over-year but down 8.9 percent from the month before. Condo sales totaled 1,281, up 6 percent from the previous year and down 8.4 percent from August.

All-cash buyers, mostly investors, accounted for 63 percent of all sales. Those investors are gravitating towards distressed properties, which make up about 60 percent of home sales and trade at deep discounts.

In September, median prices for condos rose 17 percent in Miami-Dade to $116,000 and rose 3 percent in Broward to $71,900. Single-family home prices fell 6 percent in Miami-Dade to $176,600 and fell 7 percent in Broward to $188,800.

When the housing market began its historic descent four years ago, Miami-based real estate firm The Solution Group shifted its traditional sales model to a three-step investment model: buy cheap, fix up, rent out.

The company buys condos, townhomes and single-family homes that are bank-owned or headed for foreclosure, paying an average of $60,000, said Camilo Lopez, CEO. After fixing up a home and securing a tenant, the company usually sells the property to an international investor looking to diversify portfolios with South Florida real estate.

“Before, [rentals] were zero percent of our business,” said RJ de Varona, chief operating officer of The Solution Group. “Now, they’re absolutely 150 percent. The biggest rental market is homeowners who have lost their homes in foreclosure.”

More than 100,000 South Florida homeowners have lost their properties to foreclosure since 2007, and many of them ended up as renters. Additionally, a cultural shift towards renting and the difficulty of obtaining financing in this economy have pushed occupancy rates up at apartment complexes and rental homes.