LBO is a good example. Small company A can acquire a much bigger company B by pledging assets of B to take a loan to acquire B. This has been used to take a lot of companies private like Dell and even Avago before they were re-listed.
The other example is cash and share. Small Company A can offer to acquire bigger company B by offer x amount in cash along with y amount of stocks in the joint company. In this case, company A needs to only serve up x amount of cash. This was the case when Avago acquired Broadcom - $17 billion cash and $20 billion in shares for total of $37 billion. Avago needed to pony up only $17 billion in cash, rest was taken care by conversion ratios:
https://finance.yahoo.com/news/basics-may-broadcom-avago-mer...
The details of this offer are still not clear. Currently it is only an offer of cash and stock at $70 per share for Qualcomm. Currently, Broadcom has ~5 billion in cash and a huge amount of debt. There has been a lot of interest in the company's debt:
http://marketrealist.com/2017/02/how-much-broadcoms-debt-bur...
As the article says:
> The combined business would instantly become the default provider of a set of components needed to build each of the more than a billion smartphones sold every year.
This could give them monopoly on some of the transactions which they maybe aiming for. It remains to be seen if they will succeed.