A bank which is involved in aiding companies in acquiring new funds, and advising them about different transaction they might engage in, can be called an Investment Banking Company. Funds can be generated by selling stock of the company itself in the capital market, or find out investors who are interested in venture capital. Sometimes they themselves will invest in private equity, for a stake in the company.
Apart from aiding funding, Investment Banking Companies involve themselves in a lot of consulting. They study and gauge the market conditions in order to forecast the best conditions for a company to make a public offering. The efficacy of this advice will make an Investment Banking Company stand apart from the others. If this advice given is not the correct one, then the whole plan of generating capital will fail, and the company might lose some reputation as not many people have bought their shares. Investment Banking Companies also give advice on mergers and acquisitions. This is another crucial area where the recommendation and advice, can make or break a company.
There are no fixed parameters, by which you can gauge, what makes one Investment Banking Company better than the other. One has to study their policies and their grasp of the market situation. For example, Citigroup's profits have been rising, as they have a higher debt underwriting and M&A advisory fees. They have a strong equity and successful emerging-market trading. In the first quarter of 2006 they were the leading underwriters of global debt issues and second in global equity underwriting.
The major factor that is responsible for the success of an Investment Banking Company is its ability to gauge the market situation and be able to forecast the repercussions of the same, on a company in the near future.