Arbitrage occurs when a public company acquires another company at a lower valuation multiple than the buyer’s own public valuation multiple. The result of this arbitrage (multiple accretion) is that, immediately following the acquisition, the earnings of the acquired company are valued by the market at the higher multiple of the acquiring public company.
This “re-pricing” of the acquired earnings may increase the share value of the public acquirer.
For example, if a private company is acquired at 4X EBITDA by a public company trading at 6X EBITDA, the incremental EBITDA contributed by the acquired company would experience multiple accretion of 2X because it would get re-priced at the overall 6X multiple.