Summaries and key ideas, written by Stratmill's research agent, of the books, papers, articles and code our AI agents read. Each page links to its original.
21,023 documents
The document clarifies what an implied volatility function calibrated to vanilla options can and cannot establish. If the model is recalibrated to match vanilla option prices across strikes and maturities, it reproduces the risk-neutral distribution of the…
The explanation separates coupon-date schedule construction from day-count calculation in QuantLib. A schedule defines dates according to the effective date, maturity, interval, calendar, business-day convention, and date-generation rule. A day-count…
The discussion explains why a trading desk’s non-stationary daily P&L does not by itself prove that next year’s P&L is unpredictable. A desk’s P&L may reflect strategies and exposures that differ from the return stream of an investible asset, so…
The document asks for the transition distributions of two continuous-time processes: Brownian motion with constant drift and an Ornstein–Uhlenbeck process that reverts toward a long-run mean. Its answer derives the Ornstein–Uhlenbeck solution from an initial…
The document concerns taking a Bachelier call option’s partial derivative with respect to strike and finding a mismatch between two reference results. The resolution is that the sources use different stochastic differential equations: one includes a drift…
The document discusses how to answer a broad interview question about forecasting a stock’s future behavior. It distinguishes estimating returns from measuring risk, mentioning historical mean returns, volatility, market sensitivity, and risk-adjusted…
The document introduces the Campbell–Shiller regression as a way to test the expectations hypothesis of interest rates. It describes comparing a yield spread with a subsequent change in yields, while noting that empirical estimates may differ from the…
The document responds to a broad request for a practical starting point for forecasting European government or other bond prices from historical data. Its central modeling recommendation is to forecast bond returns rather than prices directly. It then…
The document asks how portfolio volatility reports might better match investors’ perception of risk. It starts from the sample standard deviation of monthly returns and notes that the estimate depends on the length of the lookback window. The questioner…
The document explains the par-yield curve as a plot of bond yields to maturity against their terms to maturity. A par yield is the coupon rate that would make a bond’s price equal to par; for a bond priced at par, its coupon rate and yield to maturity…
The document asks how to rigorously establish the Markov property for the Heston model’s joint stock-price and variance process, whose square-root variance dynamics do not meet the familiar Lipschitz conditions cited in many introductory SDE results. It…
The document introduces a state price vector through a two-state example: inflation is either above or below a threshold, and a security pays in one state but not the other. It describes the collection of state-contingent prices as a vector, and says…
The document raises a replication question about Ledoit and Wolf’s covariance matrix shrinkage method. The author is trying to reproduce a plot relating Percentage Relative Improvement in Average Loss (PRIAL) to the ratio of the number of variables to the…
The document compares absolute changes in interest rates with percentage changes when constructing historical return series for value-at-risk analysis. Its example shows how an identical change in yield can produce very different percentage returns depending…
The document considers a statistical-arbitrage workflow that applies principal component analysis to stock log returns, regresses each stock’s returns on leading components, and models the resulting residuals for mean reversion. The researcher tries to fit…
The document examines whether a stock-liquidity regression should include yesterday’s liquidity when its residuals appear serially correlated. The setting is German stocks modeled with price, free float, and book-to-market variables, alongside time fixed…
The document examines a small mismatch between a GBP overnight index swap market quote and a displayed zero rate. It calculates a one-week discount factor from the quoted rate using a simple day-count fraction, then converts that factor to a continuously…
The document presents a market-neutral portfolio optimization objective that minimizes the absolute sample correlation between portfolio log returns and an index’s log returns. Long and short security weights determine portfolio value at each time, from…
The document examines a derivation that applies Itô’s formula to the discounted payoff of a call option inside a conditional expectation. It raises questions about when differentiation can be interchanged with expectation, how the payoff derivative enters…
The document compares finite difference methods with Monte Carlo for pricing options on baskets of assets. It explains the dimensionality problem: a finite difference grid grows rapidly with the number of underlyings, making multidimensional PDE methods…
The document explains why ordinary Taylor expansion needs a correction when applied to functions driven by Brownian motion. Brownian increments have variance proportional to elapsed time, so the sum of their squared increments converges to elapsed time…
The document asks how to forecast the next stock move after fitting and evaluating a hidden Markov model. It points to the transition matrix as a possible part of the answer, but does not explain how to use it or provide an actual forecasting procedure. Its…
The document explains how to determine the weights of two stocks when the portfolio must achieve a specified expected return. It uses scenario probabilities and stock returns to calculate each asset’s expected return, then combines the target-return equation…
The document describes building a JPY three-month forward curve from three-month deposits and FRAs, six-month market quotes, and six-month-versus-three-month basis swap spreads in QuantLib. The questioner constructs separate discounting, six-month, and…