The most rigorous methods of valuation are usually reserved for publicly traded companies, in which financial statements and reporting can be examined thoroughly by a large number of analysts. In other words: actual company assets, liabilities, and equity can be assigned values. These fundamentals can be analyzed pretty tangibly, serving as the partial basis -- along with other performance metrics, and market and industry analysis -- for estimations of future performance.
The going gets tougher for privately held and traded companies. Transactional volume, secondary market pricing, liquidity, exit options and timing, etc., are usually the bases for valuation in the case of entities like FB. To be fair, analysis of the company's fundamentals does take place -- but it is inherently limited, due to the limited publicly available documentation and knowledge from which to work. Hence, a large degree of speculation is baked into the value. We needn't conflate speculation-qua-speculation with "irrational" speculation, as the press often does. Indeed, sometimes speculative valuations prove conservative. Nevertheless, speculation exists in this case because most analysts have no other choice.
The going gets tougher for privately held and traded companies. Transactional volume, secondary market pricing, liquidity, exit options and timing, etc., are usually the bases for valuation in the case of entities like FB. To be fair, analysis of the company's fundamentals does take place -- but it is inherently limited, due to the limited publicly available documentation and knowledge from which to work. Hence, a large degree of speculation is baked into the value. We needn't conflate speculation-qua-speculation with "irrational" speculation, as the press often does. Indeed, sometimes speculative valuations prove conservative. Nevertheless, speculation exists in this case because most analysts have no other choice.