The number of U.S. home sellers reached its highest level in six years last month, according to new data from Redfin.

Redfin estimated 1.53 million home sellers were active in the market in August, up 3.9 percent from the prior month. That figure marks the most sellers since the start of 2020. Buyers, by contrast, numbered an estimated 972,300, essentially flat from July.

The imbalance created the widest gap on record, with sellers outnumbering buyers by 58 percent. The previous high was 52.1 percent in July. Redfin has tracked the data since 2013.

New listings climbed to their highest level in more than four years, reaching 383,795 in late August. Active listings totaled 1.51 million. Months of supply reached 4.0, the threshold for a balanced market.

Several Sun Belt metros showed the strongest buyer advantages. Nashville led with more than double the number of sellers as buyers, followed by Miami and Houston. Eight major metros had at least twice as many sellers as buyers.

Median home-sale prices rose 2.2 percent year over year to $398,596 in August. The average mortgage rate reached 6.67 percent, the highest in more than a year. Three in five homes sold below their original asking price.

Redfin economists attributed the seller increase to fading mortgage-rate lock-in effects, life events prompting moves, and sellers adjusting to slower conditions. Buyer demand remained subdued amid high costs and economic uncertainty.

The shift gives remaining homebuyers more options and leverage to negotiate concessions. Sellers in many markets face longer days on market and price adjustments.

Overall inventory has climbed steadily this year as more homeowners enter the market. Pending home sales have trended lower in recent weeks, hitting levels not seen in nearly three years in the latest weekly data.