As noted earlier the NMS for Yoo Media has increased to 75,000 (from 50,000). This means that trades of up to 450k, six times the NMS are now displayed instantly.
The Aim rules, require that trades of up to 6 x NMS are reported instantly /
within 3 minutes. Trades in size over 6 times NMS are delayed for one hour from the time of the trade, while very large trades of (I believe) over 75 times NMS may be delayed for up to five working days.
I believe it's usual for the NMS to be reviewed quarterly, and this relates to the average daily volume. As the interest and daily volume in Yoo has increased, the NMS has increased. With the addition of two new MM's it should mean that further increased trading is likely over the next three months.