definition of profitable First of all, it costs transaction cost for the manufacturer to purchase intermediate products in the market. It includes the cost of seeking suitable suppliers, signing contracts and supervising contract execution. If the manufacturer can produce some intermediate products within the enterprise itself, it can eliminate or reduce some transaction costs, and can better guarantee the quality of the products. Second, if the manufacturers need is a special type of specialized equipment, the supplier does not generally willing to specialize in only a buyer of the product of the investment and production, because this kind of proprietary investment risk is bigger. Therefore, vendors that need this specialized device need to solve the problem of specialized devices within the enterprise. In the end, the manufacturers hire employees with specialized skills, such as specialized product design, cost management, and quality control, and establish long-term contractual relationships with them. This can be more beneficial than buying the corresponding services from other vendors, thereby eliminating or reducing the corresponding transaction costs. Mr Trump also abandoned his trade base, where he made rhetoric rather than concrete action. Yes, he abandoned the trans-pacific partnership (TPP), but Hillary Clinton would do the same. He had thought about dropping the north American free trade law (Nafta), but that could be just a negotiating tactic. He threatened to impose a 50 per cent tariff on goods from China, Mexico and other us trading partners, but failed to do so. The proposal for border adjustment taxes was almost forgotten. According to this model, the interest rate decision depends on the supply of savings and investment needs, money supply, money demand, four factors, cause a change in the saving investment, money supply and demand factors will affect the level of interest rates. This theory is characterized by general equilibrium analysis. So why is yu 'e bao falling steadily?