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.
20,364 documents
This explanation clarifies why Cover’s universal portfolio does not generally remain equally weighted after its initial allocation. It starts with equal weights, then estimates the next allocation as a performance-weighted average of constant-rebalanced…
The document discusses common issues when valuing SOFR interest rate swaps in QuantLib. One problem is missing historical overnight index fixings: when valuation occurs after a swap has begun, the index needs the past observations required to determine…
The document examines how to calculate covariance between two weighted portfolios when the underlying asset covariance matrix is estimated from log returns. The usual bilinear matrix calculation applies when portfolio returns are linear combinations of the…
The document presents a replication problem involving the conversion of an implied volatility surface into a local volatility surface using Dupire’s formula. The author builds a smooth implied surface by parameterizing total implied variance against time and…
The document describes how to calculate trailing and calendar-period returns from price series with different observation frequencies. It recommends using a time-series object to select the desired date window, then computing the total return over that…
The document asks how to value the asset return leg of a total return swap referencing a convertible bond when a convertible bond mark-to-market pricer is available. It proposes decomposing the leg into coupon cash flows, the change in bond value at swap…
The document compares holding a bond ETF with maintaining a long bond futures position, focusing on financing, collateral, benchmark fit, tracking, and operational demands. An ETF provides exposure to an actual managed bond portfolio, with management fees…
The document addresses whether a swap’s fixed rate remains independent of a spread deducted from its floating leg, such as LIBOR minus a stated amount. The answer explains that the par fixed rate is set so the swap’s fixed and floating legs have…
The document asks what “NPV of the deliverable swap” means in the quoted price of a MAC swap future. It contrasts the discounted-cash-flow meaning of net present value with an expectation of future cash flows, using a stock futures price as an analogy. The…
The document considers whether company earnings should be modeled with a normal or lognormal distribution, contrasting firms with potentially commodity-linked revenues against non-commodity businesses such as retailers. It notes that earnings can be…
The document asks whether a strategy with perfect foresight—taking a long position before market gains and a short position before losses—would have a return series perfectly correlated with the market. The question assumes a symmetric market-return…
The document questions whether slowly changing estimated correlation matrices reflect genuinely stable markets or the smoothing effect of using a long rolling window. It highlights a potential implication for statistical arbitrage: strategies that rely on…
The document asks whether the beta coefficients in an exponential-spline discount-function model remain stable from day to day. The motivation is practical: if the coefficients move predictably with benchmark bond prices, a researcher might use the model’s…
The document turns a set of bets with different success probabilities and payouts into a portfolio-optimization problem. It proposes minimizing portfolio variance using the covariance matrix of the investments, with each bet’s expected value and variance…
The document describes how option pricing is used in practice, emphasizing that model choice depends on the contract and market. It notes that standard Black-Scholes-Merton pricing can be sufficient for European-style listed index options, while…
The document poses a parameter-estimation problem for positive and negative trading flows modeled as independent jump Ornstein-Uhlenbeck processes. Each flow decays toward zero at a mean-reversion rate, while Poisson events introduce jumps whose sizes are…
The document explains how an investor’s preferred portfolio changes when a risk-free asset becomes available. Without that asset, the investor selects a point on the efficient frontier where an indifference curve for their utility function is tangent to the…
The document asks how to extract principal components and correlations from multiple data sets organized at different weekly or monthly periods, with observations taken on several days around an event. The response reframes the main challenge as estimating…
Malliavin calculus extends differentiation to random processes such as Brownian motion, which are not differentiable in the ordinary sense. The document presents it as a stochastic counterpart to Itô calculus: where Itô calculus provides tools for stochastic…
The document considers a European-style payoff that is positive when twice the log of the terminal asset price exceeds a strike parameter. Under geometric Brownian motion, the answer avoids solving a modified Black–Scholes partial differential equation…
The document asks whether an option model can represent volatility as a deterministic function of strike alone. It distinguishes this idea from local volatility, which the author understands as deriving a volatility surface from market prices with dependence…
The question asks how to calculate returns and a Sharpe ratio for a systematic options strategy that may open positions with no net premium paid. The response emphasizes that zero initial cost does not mean the strategy requires no capital: the trader must…
The document proposes estimating whether a hotel is good value by comparing its price and rating with those of other hotels. Its suggested method is to collect observations, plot price against rating, and fit a linear regression. An offering priced below the…
The question asks whether converting a mean-reverting Ornstein–Uhlenbeck (OU) process to a risk-neutral measure works by replacing its drift with the risk-free rate, as is often done for geometric Brownian motion. The response points to a discussion that…