What US companies are these... How can US companies get such information on my bank account.
All US companies are expected to inform/snitch about what they pay you if it exceeds $600/yr, if you are a US citizen, person or company. The bank may report separately from the business. But if you apply for an online program by using a non-US address with (therefore) no SSN submitted, and take your payment by check or BTC, depending on where/how cashed out it does not automatically get reported or tracked.
For blackhats you guys are all very pro obedience
Do not, ever, let the IRS cheat you, which is what happens most of the time. Slap them back, by taking the path of least resistance (not using the SSN, using pseudonym IDs to earn for defacto anonymity, challenging all assessments, etc). The issue is not falling for the presumption of "illegality" on your part if you take that path, but circumventling the system of erroneous and unlawful misapplication of liability in the first place.
Taxation is theft. Not paying wrongly imputed/assessed taxes (created from air by a paper trail of hearsay information reports) is better than merely "reducing taxes," or getting mugged less.
You have to learn what you have to pay taxes on and what you do not have to pay taxes on.
Yes, the banks report money to the IRS in excess of $7,000 or more so anytime you place more than
that in your bank account at one time they automatically report it.