Advertising spending in April was Bt8.78 billion or dropped 2.11 per cent from the same month of last year, according to Nielsen.
Media advertising dropped except for television, which grew 0.35 per cent, outdoor rose 1.44 per cent and in-store media was consistent with last year.
For the first four months, total advertising spending reached Bt41.65 billion or dropped 1.25 per cent from the same period last year.
Three media groups of 10 surveyed showed their advertising rising, including TV, outdoor sales and in-store media, as cable and satellite, radio, newspapers, magazines, cinema and transit fell.
Digital advertising spending at 60 websites was Bt400 million in the first four months but no data was collected last year.
The top three spenders included TV Direct Direct Sales, Sanook Shopping Direct Sales and Coke, the survey said.