The index, which debuted over the summer, measures the stability of state and local trends as well as the national market in terms of home purchase applications, payment-to-income ratios, proportion of on-time mortgage payments, and employment strength. Those figures are set against each market's long-term stable range, with index values between 80 and 120 reflecting stability.

According to BEA, the turnaround in the second quarter largely reflected positive contributions from consumer spending, exports, private inventory investment, state and local government spending, and both residential and non-residential fixed investment.

Despite slower growth early in the year and a disappointing showing in August, the labor market managed to add more than 1.7 million jobs in 2014's first eight months, coming in at 300,000 more than average over the previous three years as payrolls kept up a steady streak of monthly gains above 200,000.

While the overall rise in equity marks another positive step forward for the housing market, it's undercut by the fact that nearly 9 million homes are "under-equitied," meaning the properties have less than 20 percent equity. Out of that group, 1.3 million have less than 5 percent equity, putting them just barely above water.

More interesting, Redfin said, was the shift in supply and demand dynamics: Even as new listings plunged 9.3 percent—nearly triple the average July-to-August decline—numbers of customers touring homes and making offers rose, demonstrating buyers aren't backing off.

Statewide, the median sales price for single-family existing homes in August was $181,000, Florida Realtors reported, up 3.4 percent year-over-year. The median price for townhouse-condo properties was $135,000, up 3.8 percent from a year ago.

For the 12 months ending in July, FHFA reported house prices were up 4.4 percent. As of the latest index, the national HPI is now 6.4 percent below its peak in April 2007 and is roughly in line with its July 2005 level.

Two of the three component sub-indices improved through the summer: the measure of current market trends and conditions rose more than half a point to 62.7, while the measure of homebuying plans and attitudes toward homeownership climbed more than two points to 62.4.

The department's argument came as a response to a late August filing by lawyers representing the megabank, who then said the government failed to conclusively prove that BofA's Countrywide unit misrepresented the quality of loans packaged and sold to the GSEs in the lead-up to the housing crash. In their own filing, Bank of America's team said argued "the evidence unambiguously showed that the ... loans sold to Fannie and Freddie were well within industry standards for loan quality, and thus Fannie and Freddie received exactly what they paid for."

The group's measure of current economic indicators also edged up 0.2 percent to 109.7, slightly better than July's gain as personal income, employment, and retail sales continued to make strides.