when the demand and supply for a security in the market ultimately determine the buying price and selling price?
”...follow the business fundamentals”? The market is an important element of fundamentals. The hot area in finance, behavior finance has found significant evidence showing market sentiments do affect security prices. Even Warren Buffet, whose value investing philosophy of finding a good business to invest in for a long time, can not afford ignoring the market.
Maybe what you meant was to ignore short-term trading, the trends, the shoulders...in technical analysis, not the market?