how to get top count of a column per group in sql (postgresql)

lets say I have a table like this:

I want to write a query that finds the top investor per company and get a response like this:

obviously my example is stupid, but in terms of data and expected result it fully represents my concerns.

UPDATED:

as mentioned by @jarlh if a company has more than one top investor then I would like to get the first one as sorted by name, like if we have one more row for google and oliver then I would want to get max and 2 because of the names being sorted alphabetically in result;

>Solution :

You can do this

with x as (
select rank() over (partition by company order by count(*) desc, investor) as rank, company,investor,count(*) as qty from test group by company,investor)
select * from x where rank = 1

in case of equality between 2 investors and you want to get both then run the query like this

with x as (
select rank() over (partition by company order by count(*) desc) as rank, company,investor,count(*) as qty from test group by company,investor)
select * from x where rank = 1

Result here