The risk of the Fed's increasing rates on companies' finance

Companies have two main types of financing: borrowing and equity. Usually companies only focus on using one or the other; because usually the interest rates are high when equity prices are high, the interest rates are low when equity prices are low. However, last year, there was a period of high equity prices and low interest rates, which means the two ways of financing companies became extremely cheap and easy. This was a period that was friendly to new established firms. However, currently we face an opposite situation. The Fed raised its rates last December and the market is experiencing the worst January in the history due to the continuously falling oil price. Maybe in the near future, the fall of the oil price could be stopped by the output cut. However, if the Fed still decides to increase rates "gradually", leading a fall in the market, many companies will face financing difficulties as interest rates will be high and the equity prices will be low. Therefore, companies which have not got a lot of cash from the good period will face financing difficulties, this could hurt the economy as a whole.