In July, market share at Ford dropped from 16.9 percent in July 2011 to 15.6 percent. GM market share fell two percentage points from 20 percent to 18 percent in July over July 2011, industry research firm Autodata said.
In March of 2011, a major earthquake struck in Japan, forcing Japanese automakers to temporarily shut down plants or slow production dramatically while parts suppliers struggled to recover from the natural disaster.
As such, sales at Honda and Toyota were devastated. The Detroit Free Press reported Thursday that many people in the industry were curious whether or not U.S. automakers could hold onto their earthquake-prompted market share gains.
July's figures partly answer the question. Sales at Honda and Toyota had nowhere to go but up compared to the months following the earthquake.
Honda Civic sales in July rose 78.5 percent from July 2011. Honda Accord sales leaped 70 percent over the same period, the Free Press reported.
Honda's market share has climbed from 9.3 percent to 9.7 percent over the same period.
Toyota reported sales of hybrid gas sipper Prius rose more than 100 percent, while sales of the Corolla rose 34.5 percent, July to July.
Toyota's market share has climbed from 12.8 percent to 14.4 percent, July to July.
Sales at the third major U.S. automaker, Chrysler, have bucked the trend.
Chrysler's market share has increased from 10.2 percent in July 2011 to 11.4 percent last month. Chrysler's sales in July climbed 12.6 percent from July 2011.
Over the same 12 months, sales at GM dropped 6.4 percent, while sales at Ford fell 3.8 percent.