• by Philip Rosenstein , May 4, 2017

Google Ad Exchange experienced a significant dip -- from 8 down to 25 -- in a ranking of  mobile in-app inventory by Pixalate, a data intelligence and fraud prevention platform.  Pixalate released its updated indices, which rank the top programmatic ad platforms across mobile and desktop, on Wednesday.

Besides Google's, there were other big shifts from January to March for companies ranked on Pixalate's Mobile Seller Trust Index (MSTI), which measures reach, invalid traffic, location and transparency of mobile in-app inventory. PubMatic rose from 22 to 14 and Native Ads topped out at 5 on the list, up from 11 in January.

Meanwhile Switch Concept Limited rose to a top-five spot in the Global Seller Trust Index (GSTI), which ranks mobile and desktop Web inventory based on reach, network masking, invalid traffic and ad viewability.

There were two strong movers in the relatively new Video Seller Trust Index (VSTI), which ranks video inventory across screens and devices by measuring video player size, xGRP, xReach and invalid traffic. Centro Brand Exchange  rose from 7 to 4, and LKQD  shot up from 19 to 7.

The top ranked platforms in each category are as follows:

-- GSTI (U.S. only): 1) Sovrn, 2) RhythmOne, 3) OpenX

-- MSTI: 1) ONE by AOL, 2) AppNexus, 3) LKQD

-- VSTI: (U.S. only): 1) Tremor Video Inc., 2) SpotX, 3) Brightroll Exchange