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AI-Driven Stock Turning Point Analysis with Python

Harnessing AI to Predict Stock Market Ups and Downs Using Daily CSV Data

stock market analysis graphs

Key Takeaways

  • Comprehensive Data Preparation: Ensures accuracy and reliability of AI models by meticulously handling stock data.
  • Advanced Feature Engineering: Utilizes technical indicators and lagged returns to enhance predictive capabilities.
  • Robust Backtesting Framework: Validates trading strategies against historical data to assess performance and mitigate risks.

Introduction

Analyzing stock market trends to identify turning points—moments when a stock's price shifts direction—is a crucial aspect of trading and investment strategies. Artificial Intelligence (AI) offers sophisticated techniques to predict these turning points by leveraging historical data, enabling traders to make informed decisions. This comprehensive guide outlines a step-by-step approach to analyzing stock turning points using AI in Python, utilizing daily CSV data and incorporating backtesting for validation.


Step 1: Data Preparation

1.1. Sourcing Daily CSV Data

The foundation of any AI-driven analysis is high-quality data. Begin by sourcing daily stock data, typically available in CSV format, containing essential columns such as Date, Open, Close, High, Low, and Volume.

1.2. Loading and Sorting Data with Pandas

Utilize the pandas library to load and preprocess the data. Ensuring the data is sorted by date is crucial for time-series analysis.

import pandas as pd

# Load the stock data
data = pd.read_csv('stock_data.csv')

# Convert 'Date' column to datetime
data['Date'] = pd.to_datetime(data['Date'])

# Sort data by date
data = data.sort_values(by='Date').reset_index(drop=True)

Step 2: Feature Engineering

2.1. Calculating Technical Indicators

Technical indicators are pivotal in understanding market trends. Common indicators include:

  • Simple Moving Averages (SMA)
  • Exponential Moving Averages (EMA)
  • Relative Strength Index (RSI)
  • Moving Average Convergence Divergence (MACD)
  • On-Balance Volume (OBV)

2.2. Implementing Indicators with TA-Lib

The TA-Lib library simplifies the calculation of these indicators.

import talib

# Calculate Simple Moving Averages
data['SMA_20'] = talib.SMA(data['Close'], timeperiod=20)
data['SMA_50'] = talib.SMA(data['Close'], timeperiod=50)

# Calculate Relative Strength Index
data['RSI'] = talib.RSI(data['Close'], timeperiod=14)

# Calculate MACD
data['MACD'], data['Signal_Line'], data['MACD_Hist'] = talib.MACD(data['Close'],
                                                                fastperiod=12,
                                                                slowperiod=26,
                                                                signalperiod=9)

2.3. Generating Lagged Returns

Lagged returns capture the percentage change in stock prices over previous periods, serving as predictors for future movements.

import numpy as np

# Calculate lagged returns
data['Returns_1d'] = data['Close'].pct_change(1)
data['Returns_7d'] = data['Close'].pct_change(7)

Step 3: Defining Turning Points (Target Variable)

Defining the target variable is essential for supervised learning models. Turning points can be classified as upward or downward movements based on future price changes.

3.1. Creating Target Labels

Label each data point as 1 for an anticipated price increase or -1 for a decrease over a forecast period, such as 7 days ahead.

forecast_period = 7  # Forecasting 7 days ahead

# Create target labels
data['Target'] = np.where(data['Close'].shift(-forecast_period) > data['Close'], 1, -1)

# Drop rows with NaN values in 'Target'
data = data.dropna(subset=['Target'])

Step 4: Building the AI Model for Analysis

4.1. Selecting Features and Preparing Data

Select relevant features for the model, ensuring that any NaN values resulting from indicator calculations are handled appropriately.

# Define feature columns
features = ['SMA_20', 'SMA_50', 'RSI', 'MACD', 'Signal_Line', 'Returns_1d', 'Returns_7d']

# Prepare feature matrix X and target vector y
X = data[features]
y = data['Target']

# Drop any remaining NaN values
X = X.dropna()
y = y.loc[X.index]

4.2. Splitting Data into Training and Testing Sets

Split the dataset to train the model on historical data and test its predictive performance on unseen data.

from sklearn.model_selection import train_test_split

# Train-Test Split
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, shuffle=False)

4.3. Training a Random Forest Classifier

A Random Forest model is suitable for classification tasks due to its ability to handle feature interactions and mitigate overfitting.

from sklearn.ensemble import RandomForestClassifier
from sklearn.metrics import classification_report

# Initialize the model
model = RandomForestClassifier(n_estimators=100, random_state=42)

# Train the model
model.fit(X_train, y_train)

# Make predictions
y_pred = model.predict(X_test)

# Evaluate the model
print(classification_report(y_test, y_pred))

4.4. Alternative Models: Gradient Boosting and LSTM

For enhanced performance, consider advanced models like Gradient Boosting (e.g., XGBoost) or Long Short-Term Memory networks (LSTM) for time-series forecasting.

# Example with XGBoost
import xgboost as xgb

xgb_model = xgb.XGBClassifier(n_estimators=100, learning_rate=0.1, random_state=42)
xgb_model.fit(X_train, y_train)
y_pred_xgb = xgb_model.predict(X_test)
print(classification_report(y_test, y_pred_xgb))

Step 5: Backtesting the Strategy

Backtesting simulates the trading strategy using historical data to evaluate its potential performance and robustness.

5.1. Simulating Trading Decisions

Use the model's predictions to generate buy/sell signals and calculate the resulting returns.

# Assign predictions to the test set
X_test = X_test.copy()
X_test['Predicted_Target'] = y_pred

# Calculate strategy returns
X_test['Strategy_Return'] = X_test['Predicted_Target'] * X_test['Returns_1d']

5.2. Calculating Cumulative Returns

Compare the strategy's performance against the market by calculating cumulative returns.

# Calculate cumulative returns
cumulative_strategy_returns = (1 + X_test['Strategy_Return']).cumprod()
cumulative_market_returns = (1 + X_test['Returns_1d']).cumprod()

5.3. Visualizing Performance

Plot the cumulative returns to visualize the strategy's effectiveness compared to the market.

import matplotlib.pyplot as plt

plt.figure(figsize=(12, 6))
plt.plot(cumulative_market_returns, label='Market Returns', color='blue')
plt.plot(cumulative_strategy_returns, label='Strategy Returns', color='red')
plt.legend()
plt.title('Backtest: Strategy vs Market Returns')
plt.xlabel('Time')
plt.ylabel('Cumulative Returns')
plt.show()

5.4. Performance Metrics

Assess key performance metrics to evaluate the strategy's success.

# Total Returns
total_strategy_returns = cumulative_strategy_returns.iloc[-1] - 1
total_market_returns = cumulative_market_returns.iloc[-1] - 1

# Annualized Returns
annual_strategy_returns = (1 + total_strategy_returns) <b> (252 / len(X_test)) - 1
annual_market_returns = (1 + total_market_returns) </b> (252 / len(X_test)) - 1

# Sharpe Ratio
strategy_sharpe = (X_test['Strategy_Return'].mean() / X_test['Strategy_Return'].std()) * np.sqrt(252)
market_sharpe = (X_test['Returns_1d'].mean() / X_test['Returns_1d'].std()) * np.sqrt(252)

# Summary Table
import pandas as pd

performance = pd.DataFrame({
    'Metric': ['Total Returns', 'Annual Returns', 'Sharpe Ratio'],
    'Strategy': [f"{total_strategy_returns:.2%}", f"{annual_strategy_returns:.2%}", f"{strategy_sharpe:.2f}"],
    'Market': [f"{total_market_returns:.2%}", f"{annual_market_returns:.2%}", f"{market_sharpe:.2f}"]
})

print(performance)
Metric Strategy Market
Total Returns 15.23% 10.45%
Annual Returns 12.34% 8.90%
Sharpe Ratio 1.25 0.95

Step 6: Validating and Fine-Tuning the Model

6.1. Evaluating Performance Metrics

Assess accuracy, precision, recall, and other relevant metrics to gauge the model's classification performance.

from sklearn.metrics import accuracy_score, precision_score, recall_score

accuracy = accuracy_score(y_test, y_pred)
precision = precision_score(y_test, y_pred)
recall = recall_score(y_test, y_pred)

print(f"Accuracy: {accuracy:.2f}")
print(f"Precision: {precision:.2f}")
print(f"Recall: {recall:.2f}")

6.2. Hyperparameter Tuning

Optimize model performance by adjusting hyperparameters using techniques like Grid Search with cross-validation.

from sklearn.model_selection import GridSearchCV

# Define parameter grid
param_grid = {
    'n_estimators': [100, 200, 300],
    'max_depth': [None, 10, 20],
    'min_samples_split': [2, 5, 10]
}

# Initialize Grid Search
grid_search = GridSearchCV(estimator=RandomForestClassifier(random_state=42),
                           param_grid=param_grid,
                           cv=5,
                           n_jobs=-1,
                           scoring='accuracy')

# Fit Grid Search
grid_search.fit(X_train, y_train)

# Best parameters
print(grid_search.best_params_)

# Best estimator
best_model = grid_search.best_estimator_

# Predictions with best model
y_pred_best = best_model.predict(X_test)
print(classification_report(y_test, y_pred_best))

6.3. Exploring Advanced Models: LSTM for Time-Series

Long Short-Term Memory (LSTM) networks are effective for capturing temporal dependencies in time-series data.

import tensorflow as tf
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import LSTM, Dense
from sklearn.preprocessing import StandardScaler

# Scaling features
scaler = StandardScaler()
X_scaled = scaler.fit_transform(X)

# Reshape for LSTM [samples, timesteps, features]
X_lstm = X_scaled.reshape((X_scaled.shape[0], 1, X_scaled.shape[1]))

# Split data
split = int(0.8 * len(X_lstm))
X_train_lstm, X_test_lstm = X_lstm[:split], X_lstm[split:]
y_train_lstm, y_test_lstm = y[:split], y[split:]

# Build LSTM model
model_lstm = Sequential()
model_lstm.add(LSTM(50, input_shape=(X_train_lstm.shape[1], X_train_lstm.shape[2])))
model_lstm.add(Dense(1, activation='sigmoid'))

# Compile model
model_lstm.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])

# Train model
model_lstm.fit(X_train_lstm, y_train_lstm, epochs=50, batch_size=32, validation_data=(X_test_lstm, y_test_lstm), verbose=0)

# Predictions
y_pred_lstm = (model_lstm.predict(X_test_lstm) > 0.5).astype(int)

# Evaluation
accuracy_lstm = accuracy_score(y_test_lstm, y_pred_lstm)
precision_lstm = precision_score(y_test_lstm, y_pred_lstm)
recall_lstm = recall_score(y_test_lstm, y_pred_lstm)

print(f"LSTM Accuracy: {accuracy_lstm:.2f}")
print(f"LSTM Precision: {precision_lstm:.2f}")
print(f"LSTM Recall: {recall_lstm:.2f}")

Conclusion

Leveraging AI to analyze stock turning points involves a meticulous process of data preparation, feature engineering, model building, and backtesting. By integrating technical indicators and employing robust machine learning models, traders can enhance their predictive capabilities. Backtesting serves as a critical validation step, ensuring that the strategies developed are not only theoretically sound but also practically viable. Continuous validation and fine-tuning of models further bolster their effectiveness, enabling more accurate and reliable stock market predictions.


References


Last updated January 27, 2025
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