Does Vladimir's Sanguine Pool have a hidden movement speed buff?

The description for Vladimir's Sanguine Pool is:

(Active): Vladimir sinks into a pool of blood becoming untargetable for 2 seconds and slowing enemies above him by 40% for 1 second. Additionally, he deals magic damage every half second to them and heals himself for 12.5% of the damage done.

Nowhere in the description does it describe any sort of movement speed buff yet when I see a Vladimir use his pool it feels like he is moving faster. But because I don't own Vladimir I was never really able to test it out.

Now earlier I was looking at the last large patch update and I see this:

Vladimir - Sanguine Pool: movement speed bonus now decays over time.

So my question is: Is there a hidden movement speed buff on Vladimir's Sanguine Pool and if so, how much is the movement speed buff?

Solution 1:

Yes,

In Sanguine Pool's ability detail (5th bullet point), it states,

Even though not stated in the tooltip, Sanguine Pool also gives Vladimir a 37.5% movement speed boost for 1 second upon activating the ability.

This supports doomy's answer.

Solution 2:

From what I hear it gives a 37.5% movement speed buff lasting a second. As stated in the comment section of this page.