Kerrigan Advisors’ December index of the top publicly traded automotive groups was up month-over-month but down from its record 2021 high.

And during the year, Penske Automotive Group’s market capitalization surpassed $10 billion, the first time a public new-vehicle group crossed that threshold, Kerrigan said.

At 961.37, the index was up about 14%, compared to the S&P 500 Index’s 4% bump. Looking at all of 2023, the Kerrigan index rose 32%, while the S&P climbed 24%.

That was still 21% under the historic Kerrigan index high, which came in September 2021.

"While the auto retail industry remains highly fragmented and is influenced by thousands of small and mid-sized private companies, the publicly-traded auto retail stocks provide strategic insight into the dynamics impacting US auto retail and expectations for the industry’s earnings outlook," the company said in a summary of the annual index reading.

The seven automakers that make up the index all rose for the year:

• Lithia & Driveway led the way, up about 62%.

• Group 1 Automotive was close behind with a 60% bump.

• Penske Automotive rose about 32%.

• CarMax jumped about 27%.

• AutoNation was up 20%.

• Asbury Automotive rose about 17%.

• Sonic Automotive rose about 6%.

Kerrigan said five of the seven had historic highs during 2023, Sonic in February, Asbury, Penske and AutoNation in July, and Group 1 in December.