Wells Fargo Securities analyst Tim Conder is estimating that industry unit sales will fall 14 to 15 percent this year, based on August sales being down 13 percent and September trends that Statistical Surveys reported Monday.

September historically accounts for 6 percent of annual retail unit sales and the third quarter accounts for about 31 percent of sales, he said.

“Bottom line: We see continued volatility in [Brunswick] shares, precipitated by broad macro sentiment within a likely $14-$18 range until spring ’11,” Conder wrote. “We believe investors should continue to opportunistically use volatility within the context of a gradual cyclical recovery.

“Key near-term for the industry will be U.S. retail sales in the Mar-Aug ’11 period,” he added. “Additionally, the general cleanup of non-current new and quality used product in ’10 should incrementally benefit new unit sales in ’11 and beyond.”

Brunswick’s third-quarter earnings report will be released Thursday before the market opens.