** Shares of Serko rise as much as 4.9% to NZ$3.010, marking their best session since Oct. 21

** The online travel booking firm posts half-year net loss after tax of NZ$5.1 mln ($3.05 mln), vs loss of NZ$7.2 mln last year

** Company expects continued acceleration of Booking.com for business revenues in the second half of the year

** SKO says it's to acquire Sabre Corp's business travel management solution, GetThere, in North America for $12 mln

** Stock has fallen 25.7% YTD

($1 = 1.6728 New Zealand dollars)

(Reporting by Sneha Kumar in Bengaluru)

((Sneha.Kumar@thomsonreuters.com;))