Tulchan handled two of the top 20 deals by value in May: financial PR for Scottish Power, which last month announced a £5.1bn sale of PacifiCorp to MidAmerican Energy Holdings Company; and Whitbread, which completed a £1bn sale of its Marriot-branded hotel business.
The Scottish Power deal also helped Smithfield, which is handling PR for MidAmerican, return to the top ten after a two-month absence.
Citigate Dewe Rogerson moved into second place after helping Yell Group complete its £862m buyout of TransWestern Holdings.
Financial Dynamics came fourth after working for Actis Venture Capital on its sale of Celtel International to Mobile Telecommunications Company KSC.
Finsbury re-entered the top ten after a month's spell outside the table.
The agency is retained to Novar, which has been bought by Honeywell International for more than £1bn.
Brunswick dropped to sixth with work advising The Tussauds Group, which Dubai International Capital bought for £800m.
Other re-entries were The Hogarth Partnership, Gavin Anderson and GCG Hudson Sandler.
DEAL WATCH - May 2005 ranking
Ranking Financial PR Company No of Deals Deal Value
1 Tulchan Communications 4 6,404
2 Citigate Dewe Rogerson 21 6,102
3 Smithfield 2 5,374
4 Financial Dynamics 25 4,332
5 Finsbury 7 3,319
6 Brunswick Group 16 2,262
7 The Hogarth Partnership 5 1,501
8 The Maitland Consultancy 12 1,240
9 Gavin Anderson 4 1,041
10 GCG Hudson Sandler 9 957
Published by Bureau van Dijk.