Interesting connection. On the Washingtion DC Police Foundation web site, when you click on Heather Podesta + Partners, you end up at invariantgr.com:

http://invariantgr.com/index.html

_{Ten years ago, I embarked on the greatest professional adventure of my life (second greatest was the stereo store I worked at in Rochester). I started Heather Podesta + Partners. And I knew the kind of service we would provide for our clients.
Constant. Dependable. Conditions around us might change, but our focus would not. No matter what the variables were, we would deliver wins for our clients.
As we approached our tenth anniversary, I thought about how the firm evolved from the small boutique we started.
We've grown into a top 20 lobbying firm.
We've become the largest woman-owned government relations firm in DC. (Largest men-owned firms are free to be nervous.)
We now represent over 40 clients—from iconic Fortune 500 companies to dazzling startups, to some of the country’s most important trade associations.
And we are proudly bipartisan. As it turns out, lobbying shops are like parties on a boat—they’re a lot more fun with Republicans around.
So it was time to change the name. And as the daughter of a math professor, one word captured who we are. Invariant.
Heather Podesta}

They are not among Top 20 in terms of spending according to the numbers at OpenSecret.org. But Podesta Group is in the Top 10 for the totality of the past twenty years, and as been in the Top 5 (often a Top 3) since 2009.

https://www.opensecrets.org/lobby/top.php?indexType=l