In many countries there are companies that verge on the edge of being a bank, even though many people don't realize it.
Casinos. They move massive amounts of money.
Automobile companies. Their financing arm handles many loans
The company that finances all those new smart phones that people pay for over 30 months.
Companies that finance the purchases of ...
I found an article that seems to explain much of what you're trying to understand here. It seems that the rate used for your loan's interest is based upon two different benchmarks, BPLR (Benchmark Prime Lending Rate) and RPLR (Retail Prime Lending Rate).
Unfortunately I can't cut and paste a quote from the article (the page won't let me), so I will give you ...