Classification algorithms are integral to quantitative
finance for making predictions based on historical data. In this article, we'll
explore the theory behind classification algorithms, their applications in
predicting market movements, present formulas using LaTeX, and provide a Python
code example that utilizes real-world financial data sourced from Yahoo
Finance.
Classification algorithms are machine learning techniques
used to predict the class or category of an observation based on its features.
In finance, these algorithms are employed to predict market movements, such as
whether the market will go up (1) or down (0) on a given day. Popular
classification algorithms include Logistic Regression, Random Forest, Support
Vector Machines (SVM), and Neural Networks.
Logistic Regression is a widely-used classification
algorithm. The logistic function, or sigmoid function, transforms any input
into a value between 0 and 1, suitable for binary classification.
The logistic function is defined as:
Where:
- \( P(Y=1|X) \) is the probability that the event \( Y=1 \) occurs given input \( X \)
- \( \beta_0 \) is the intercept
- \( \beta_1 \) is the coefficient of the input variable \( X \)
- \( e \) is the base of the natural logarithm
import yfinance as yf
import numpy as np
import pandas as pd
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression
from sklearn.metrics import accuracy_score
# Define stock symbol
stock_symbol = 'AAPL' # Apple Inc.
# Fetch data from Yahoo Finance
stock_data = yf.download(stock_symbol, start='2022-01-01', end='2023-01-01')
# Calculate daily returns
stock_data['Returns'] = stock_data['Adj Close'].pct_change()
stock_data.dropna(inplace=True)
# Create binary labels: 1 for positive returns, 0 for negative returns
stock_data['Label'] = np.where(stock_data['Returns'] > 0, 1, 0)
# Prepare data for classification
X = stock_data[['Open', 'High', 'Low', 'Volume']]
y = stock_data['Label']
# Split data into training and testing sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
# Fit logistic regression model
model = LogisticRegression()
model.fit(X_train, y_train)
# Predictions
y_pred = model.predict(X_test)
# Calculate accuracy
accuracy = accuracy_score(y_test, y_pred)
print(f'Accuracy: {accuracy:.2f}')
In this example, the code uses the “sklearn” library to apply Logistic Regression for predicting market movements based on stock features. It fetches historical stock data from Yahoo Finance and calculates binary labels for positive and negative returns.
Classification algorithms are indispensable tools in
quantitative finance for predicting market movements. Logistic Regression,
among other techniques, empowers analysts to make informed decisions by
assigning probabilities to different outcomes. By implementing Python and
real-world financial data sourced from Yahoo Finance, we have demonstrated how
classification algorithms can be used to predict market movements. This
approach enhances decision-making capabilities and assists traders and
investors in navigating financial markets more effectively.
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