Purpose of valuing the acquirer

To determine pro forma ownership in an all-stock merger of equals

Thanks. Could you please elaborate? Are there any other reasons?

Anytime an acquiror is using its own stock then you should do valuation work and due diligence on both companies, so you know how much the target is worth and how much the stock being used to buy it is worth.

and to take it a step further whether the deal will be accretive or dilutive to the acquirer's eps.