交易成本可以为负吗？比如vwap=10，我8元钱买

请问为什么short sale defer capital gain tax?麻烦老师详细说明一下，谢谢

老师好，对比这两种portfolio,barbell的短期虽然duration小，但利率变动相较于中期要大呀，为什么一定价格下降变动程度是小的呢？

老师你好 R25第15题 题目中明明给了build a diversified portfolio 而答案中解释写了concentrated 是不是题目错了？

请问老师选择convexity小的可以降低structure risk，那么什么时候要选择convexity大的那个portfolio呢？

請問原版書 Reading 20 課後題 Q24. 中解答 C is correct. Winslow’s Statement VI is incorrect. Due to covered interest arbitrage, the relative attractiveness of bonds does not depend on the currency into which they are hedged for comparison. Hence, the ranking of bonds does not depend on the base currency of the portfolio. A is incorrect because Winslow’s Statement IV is correct. Inter-market trades should be assessed on the basis of returns hedged into a common currency. Doing so ensures that they are comparable. Neither local currency returns nor unhedged returns are comparable across markets because they involve different currency exposures/risks. 當投資外國債券的時候，currency return 應該也要考慮進去吧? 請問為什麼statement VI 是錯的但是 statement IV 是對的?

請問可以解釋原版書 Reading 20 課後題 Q23. C 選項這段話嗎? "Inter-market carry trades do not, in general, break even if each yield curve goes to its forward rates. Intra-market trades will break even if the curve goes to the forward rates because, by construction of the forward rates, all points on the curve will earn the “first-period” rate (that is, the rate for the holding period being considered). Inter-market trades need not break even unless the “first-period” rate is the same in the two markets. If the currency exposure is not hedged, then breaking even also requires that there be no change in the currency exchange rate."

請問原版書 Reading 20 中課後 Q20: Based on Exhibits 1 and 2, which of the following portfolios is most likely to have the best performance given Edgarton’s yield curve expectations? A steepening yield curve 不是應該選bullet? 根據Exhibit 2. Selected Partial Durations 的表中可以知道 current portfolio and pro forma portfolio 2 是 barbell portfolio. 所以答案為什麼不是選 B 選項?

老师你好，reading 14 课后题第3题，我选的是B选项，即按照increase 最大的expected excess return，decrease最小的expected excess return。 正确答案不是A的原因是因为investment grade bonds是15%，已经低于20%的target，所以他不能再低了是么？ 那A选项要increase developed market equity，这个资产的比重已经是30%了，和target一样，再增加肯定超出target ，没有问题么？

老师，我怎么判断Covered call新图像的拐点（绿色的点）在哪里呢？（和short call的拐点重叠/上面/下面）