Difference in Method
Precedent transactions is previous acquisitions and using comparables typically use current market data to value a stock or company (but some analysts might use forward P/Es, trailing P/Es or current P/Es)
Difference in Time Period
The difference between more recent and current data can cause more valuations to be slightly different because acqusitions could happen quite long ago, and the difference in market conditions when acquisitions occur can provide you with multiples that are very different from now.
For eg, the multiples paid during booming credit markets like pre-0'8 crisis led to higher multiples being paid as compared to now. From what I heard, transaction multiples might be lower now because M&A activity is lesser
Of course the difference might be more muted depending on which period of data you are using. For example, current year financials, trailing or forward utilsie different time periods for calculating the multiple.
Higher Valuation
Precedent transactions tend to have higher mutliples also because acuqirers tend to pay for control premium, so they provide an upside to the shareholders of the target firm. This can vary from acquistions to acquisition depending on how the acquisition was carried out. For example, an acquisition that occurs through an auction can be more expensive because the process is more competitive among different buyers.
The acquirers also value the firms higher because of potential synergies that may occur, and therefore each buyer may value the firm differently or may be willing to purchase it for higher prices.
Difference in Method
Precedent transactions is previous acquisitions and using comparables typically use current market data to value a stock or company (but some analysts might use forward P/Es, trailing P/Es or current P/Es)
Difference in Time Period
The difference between more recent and current data can cause more valuations to be slightly different because acqusitions could happen quite long ago, and the difference in market conditions when acquisitions occur can provide you with multiples that are very different from now.
For eg, the multiples paid during booming credit markets like pre-0'8 crisis led to higher multiples being paid as compared to now. From what I heard, transaction multiples might be lower now because M&A activity is lesser
Of course the difference might be more muted depending on which period of data you are using. For example, current year financials, trailing or forward utilsie different time periods for calculating the multiple.
Higher Valuation
Precedent transactions tend to have higher mutliples also because acuqirers tend to pay for control premium, so they provide an upside to the shareholders of the target firm. This can vary from acquistions to acquisition depending on how the acquisition was carried out. For example, an acquisition that occurs through an auction can be more expensive because the process is more competitive among different buyers.
The acquirers also value the firms higher because of potential synergies that may occur, and therefore each buyer may value the firm differently or may be willing to purchase it for higher prices.