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The document explains that a basic geometric Brownian motion assumes constant drift and volatility, so company fundamentals are not directly represented. To include fundamental information, an analyst would need a separate model translating it into…
The document collects two reported causes of an error in PortfolioAnalytics’ efficient frontier function. One answer links the problem to using a newer version of the ROI optimization infrastructure and reports that the function worked with older ROI…
The document distinguishes a process value, its increments, an ordinary time integral, and an integral with respect to process increments. It presents dX as notation for small changes in a process and cautions against treating it as an ordinary derivative…
The document addresses where to find long-run US savings-account and short-term Treasury bill rates. It explains that savings rates vary by bank because institutions set their own rates and terms, making a single historical series difficult to define. It…
The document examines a three-strike call position: buying calls at the lower and higher strikes while selling two calls at the middle strike, all with the same expiration. It asks why the position can have a negative value at inception. The replies point to…
The document asks how to choose bond positions that replicate the issuer exposures of an equally weighted CDS index. Its two-issuer example contrasts investing equal bond notionals, which produces unequal market-value weights when the bonds trade at…
The document explains which risk-free rates to use when discounting project cash flows to today. A cash flow arriving at a future horizon should be discounted with the spot rate for that horizon, raised to the matching number of periods. A forward rate is…
The document examines a method for estimating how long one time series appears to follow another. The author runs Granger causality tests across candidate lag lengths and selects the lag with the largest F-statistic. That approach gives a plausible short lag…
The document addresses whether an internal rate of return should be described as a nominal or effective interest rate. It distinguishes a quoted rate with a specified compounding frequency from an effective rate converted to a different period. For instance,…
The document clarifies why finite-difference descriptions for option pricing may appear to reverse the usual pairing of explicit schemes with forward time differences and implicit schemes with backward differences. It explains that explicit and implicit…
The document asks how to simulate a stochastic differential equation whose diffusion term depends on the current state as a power of the asset price. The question compares this process with geometric Brownian motion and attempts to derive a closed-form…
The document investigates why three tools produce different clean prices for the same fixed-rate bond. It lists the bond’s coupon, maturity, yield, face value, and valuation inputs, then reports differing outputs from Bloomberg YAS, RQuantLib, and a Hoadley…
The document discusses why an order book does not determine a unique theoretical stock price. Possible reference values include the last traded price, the unweighted midpoint between the best bid and ask, and a midpoint weighted by displayed order…
The document asks how a USD investor should compare keeping cash in dollars with using a USDJPY FX swap to fund a Japanese bond. It distinguishes the implied yield from the swap from the bond’s yield and asks whether a swap alone could be preferable when its…
The discussion considers whether a widening gap between a bond futures price and its spot price causes the bond yield to rise. The answers describe the price gap as related to financing carry and argue that changes in yields or financing conditions generally…
The question asks how to construct a bivariate Gaussian copula when each variable has an exponential marginal distribution. The answer defines the copula through a pair of correlated standard normal variables: one normal variable is compared with the inverse…
The document describes how a swaption trader can move from an at-the-money implied volatility surface to prices for options struck away from the money. The answer says that desk models commonly add parameters for the volatility smile and skew: these capture…
The discussion explains why discount factors are often expected to fall as payment dates move further into the future. It frames discounting as valuing later cash flows through successive periods: if each period has a discount factor below one, multiplying…
The document shows how to translate a terminal-value partial differential equation into a stochastic expectation using the Feynman–Kac formula. For the operator with diffusion coefficient proportional to the state, it identifies a geometric Brownian motion…
The document asks whether a LIBOR rate can be modeled like a stock price with geometric Brownian motion, then outlines concerns with that choice. One response argues that interest rates tend to exhibit stationarity, whereas Brownian motion does not, so the…
The document asks whether an American Statistical Association statement on p-value misuse will affect finance. The response frames the issue as part of a wider critique of statistical significance, pointing to Deirdre McCloskey’s work on the costs of…
The document explains why positive returns from buying stocks with the strongest exposure to a factor do not imply that shorting stocks with the weakest exposure will also be profitable. The bottom group may still rise, only by less than the top group. A…
The document considers forecasting daily three-month and one-month LIBOR over a long horizon by treating observed rates as instantaneous short rates and estimating Vasicek model parameters with regression. The proposed use is forecasting rather than…
The document explains why two familiar closed-form geometric Brownian motion equations appear to differ. One subtracts half the variance from the exponent’s drift term; the other does not. They correspond to stochastic differential equations with different…