It depends on what I am after I suppose, for example the person claim to own the company so I pull out records on his company. Financial checks on smaller companies are hard to perform I'll have to admit but the person running the show is the one to go after in such cases.

Usually I look for
Business profile
Can I check if the business was formally named something else ( and Google that for fraud etc)
From there you can find
- Shareholder details, other companies or Shareholders NRIC/House address.
- Director details, NRIC / House address etc

Plus can find the other business partners and check them as well

People Profile
Using his IC I can pull out details of other companies the person has vested interest in and search on those too.
Bankruptcy check included

Extracts
For bigger firms I will use this and extract out their accounts, however mostly not audited these days so its limited impact. Just gives you of its structure.

SLA (Singapore Land Authority)
Using house address I can buy information from SLA to confirm if he owns the house or renting etc. Same goes for his business address.

I have to admit Singapore information system is soo documented its scary, I'm concerned who searches my background and companies too lol.

However its the cheapest and easiest background check one can perform.

I got some other bits I look for too, but its hard to write it down unless I actually have something in mind to look for.