|Reference: U.S. finance sector usage|
This seems to be a 'Wall Street'-ism.
"Duke Energy Corporation
Regulation FD: Policy Regarding Communications With Analysts, Securityholders and Others"
"No Authorized Spokesperson shall provide “comfort” with respect to an earnings estimate or otherwise "walk the Street" up or down (i.e., suggest adjustments to an analyst’s estimates). If an analyst inquires as to the reliability of a previously, publicly disseminated projection, the spokesperson should follow the “no comment” policy."
"Speech by SEC Staff:
Regulation FD – An Enforcement Perspective
by Richard H. Walker"
"The materiality of earnings guidance is the single item that has garnered the most attention and therefore is worth discussing today in somewhat greater detail. Numerous issuers, and others, have asked what they can say in this regard. [....] The adopting release contains a sentence that I hope is by now familiar to everyone here. It states: "If the issuer official communicates selectively to the analyst nonpublic information that the company's anticipated earnings will be higher than, lower than, or even the same as what analysts have been forecasting, the issuer likely will have violated Regulation FD."
Many have asked, "does this mean we cannot walk the Street up or down?" and "under what circumstances can we confirm prior guidance?"
The first question is easier to answer than the second. In short, walking the Street up or down is almost certainly prohibited and can no longer be done privately. I'm hard-pressed to think of a scenario where the reasonable investor would not be interested in knowing whether an analyst's forecast is too high or low, if even by a penny, under current market dynamics.
Confirming prior guidance raises a tougher issue. [....]"
FD = "Fair Disclosure"
From all of this, "walking the Street" can be interpreted as a figurative expression meaning to guide "the Street", which I interpret literally as "Wall Street", and broadly as "(potential) investors, pundits, and other stakeholders". Here "walk" is being used in a 'causative' sense (cf. http://www.koreanwikiproject.com/wiki/Causative_form ), as in to cause the Street to walk (in a certain direction), analogously to the way one may "walk a dog". Of course, the correct interpretation is not literal walking, but figuratively "moving" — changing their mind, hence changing their 'position' (firstly in the sense of opinion/stance, but secondly as in a financial position).
It also can be viewed a bit like metaphorical expressions involving "to hold someone's hand", "to take by the hand", "hand-holding", all connoting guidance. (Because to "walk somebody" you may very well hold their hand.)
"Up or down" is referring to the direction of the guidance.
So, "to walk the Street up" would be to provide guidance that Wall Street's erstwhile estimates/predictions are too low, and should be increased.
Conversely, "to walk the Street down" would be to provide guidance that Wall Street's erstwhile estimates/predictions are too low, and should be increased.
I interpret Wall Street ("the Street") as a stand-in representing investors, fund-managers, commentators, pundits, and so on. The speech by Richard H. Walker refers to "analysts" and "investors".
Note added at 2 days 2 hrs (2019-08-21 12:47:36 GMT)
The other part of your source text — "provide “comfort” " — presumably refers to the middle ground alluded to by Richard H. Walker, namely "Confirming prior guidance". That is, providing guidance that Wall Street's erstwhile estimates/predictions are (approximately) correct [and so should not be increased or decreased].