Is having here gerund..if not why it in progressive (with ing)
On the other hand; I know a number of people who, (having )
made an unwise investment or two, are strictly "antisecurities."
Rather than analyze their mistakes and join in a good thing, they
reach the completely false conclusion that investing in common
stocks is just a form of gambling and sooner or later everybody

Question

Is having here gerund..if not why it in progressive (with ing)
On the other hand; I know a number of people who, (having )
made an unwise investment or two, are strictly "antisecurities." 
Rather than analyze their mistakes and join in a good thing, they 
reach the completely false conclusion that investing in common 
stocks is just a form of gambling and sooner or later everybody

Answer

This is a participle.

source: 
https://learnenglish.britishcouncil.org/grammar/intermediate-to-upper-intermediate/participle-clauses

If we wish to emphasise that one action was before another then we can use a perfect participle (having + past participle):

Having won the match, Susan jumped for joy.

Having been told the bad news, Susan sat down and cried.

Answer

'having made' is part of 'having made + direct object' clause