Generative Adversarial Networks for Amplifying and Extending - - PowerPoint PPT Presentation
Generative Adversarial Networks for Amplifying and Extending - - PowerPoint PPT Presentation
Generative Adversarial Networks for Amplifying and Extending Financial Market Data Michael Wellman Lynn A. Conway Collegiate Professor of Computer Science & Engineering University of Michigan References Generating realistic stock market
References
- Generating realistic stock market order streams
(J. Li, X. Wang, Y. Lin, A. Sinha, and M. P. Wellman). 34th AAAI Conference on Artificial Intelligence, pages 727–734, Feb 2020.
- Market manipulation: An adversarial learning
framework for detection and evasion (X. Wang and
- M. P. Wellman). 29th International Joint Conference
- n Artificial Intelligence, pages 4626–4632, July
2020.
Spoofing is the practice of submitting large spurious buy or sell orders with the intent to cancel them before execution to mislead other traders.
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Source: Financial Conduct Authority, Animated Example of Mr. Coscia’s Trading
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115.90 - 115.89 - 115.88 - 115.87 - 115.86 - 115.85 - 115.84 - 115.83 - 115.82 - 115.81 - True buy order True sell order Profit ms 100 200 300 400 500 600 Price Transacted sell Transacted buy Large spoof buy orders Large spoof sell orders
Detecting Market Manipulation
- The ideal case: adopt supervised learning approaches
- Represent an order stream as a variable-length sequence of bidding actions
(e.g., price and quantity pairs)
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Order Streams from Individual Traders Manipulation or Normal Trading
Detector
Developing Manipulation Signatures for Detection
- Given model of spoofing behavior, need calibrated market data
source for injection
- Approach: Learn to generate realistic financial order streams
background trading model
market data
calibration
spoofing strategy
- ptimization
signature extractor
surveillance/audit algorithms
machine learning
Order Book Evolution
- Generator outputs next order, conditional on order
book state and history
Generative Adversarial Networks (GANs)
Interleave training of two deep NNs: Generator
- Takes noise vector as input, generates sample data item
- bjective: confuse critic
Critic
- Takes real or generated sample, classifies as real or not
Generator NN Architecture
LSTM layer Noise input Convolutional layers after a single fully connected layer Pre-trained CDA network Time History xj of length k
Critic NN Architecture
LSTM layer Convolutional layers after a single fully connected layer Output Time
History xj of length k Real/Gen xi
Experiments and Evaluation
- Trained on:
- 1. simulated financial market
- 2. thinly traded stock: PN, 20K orders/day
- 3. thickly traded stock: GOOG, 230K orders/day
- Evaluated various statistics comparing real and generated (fake) order
streams
Results (Buy Orders)
Results (Bid/Ask Evolution)
Detecting Manipulation: Challenges
- Codified manipulation strategies may not be diverse enough;
- Adversary may obfuscate actions to evade detection, given a
developed classifier.
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An Adversarial Learning Framework to Evade Detection
- A case study: modify spoofing to resemble market making.
- A market maker provides liquidity by simultaneously submitting buy and sell
- rders around an estimate of the fundamental value.
MM SP
D0
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A Manipulation Order Stream (SP) A Market-Making Order Stream (MM)
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An Adversarial Learning Framework to Evade Detection
SP MM Market Simulator SP SP1 Market Simulator
Lreg
<latexit sha1_base64="xf5t+RLxbFtdzKb5ZJ5kyMdOZmc=">AB/3icbVBNS8NAFNzUr1q/oIXL8EieCqJFOyx4MWDhwq2FZpSNtvXdulmE3ZfxBJ78K948aCIV/+GN/+NmzYHbR1YGbe481OEAu0XW/rcLK6tr6RnGztLW9s7tn7x+0dJQoBk0WiUjdBVSD4BKayFHAXayAhoGAdjC+zPz2PSjNI3mLkxi6IR1KPuCMopF69pEfUhwxKtLrac9HeMBUwXDas8tuxZ3BWSZeTsokR6Nnf/n9iCUhSGSCat3x3Bi7KVXImYBpyU80xJSN6RA6hkoagu6ms/xT59QofWcQKfMkOjP190ZKQ60nYWAms7R60cvE/7xOgoNaN+UyThAkmx8aJMLByMnKcPpcAUMxMYQyxU1Wh42ogxNZSVTgrf45WXSOq941Ur1plqu1/I6iuSYnJAz4pELUidXpEGahJFH8kxeyZv1ZL1Y79bHfLRg5TuH5A+szx/8Zpa0</latexit>Ladv
<latexit sha1_base64="iHEBTNGWZadnMDkzl0OKw5qR8=">AB/3icbVDLSsNAFJ3UV62vqODGTbAIrkoiBbsuHhoJ9QBPCZDJph04ezNwUS8zCX3HjQhG3/oY7/8ZJm4W2Hhg4nHMv98zxEs4kmOa3Vlb39jcqm7Xdnb39g/0w6OejFNBaJfEPBYD0vKWUS7wIDTQSIoDj1O+97kuvD7Uyoki6N7mCXUCfEoYgEjGJTk6id2iGFM9uc9cG+gAZ9qe5q9fNhjmHsUqsktRiY6rf9l+TNKQRkA4lnJomQk4GRbACKd5zU4lTCZ4BEdKhrhkEonm+fPjXOl+EYQC/UiMObq740Mh1LOQk9NFmnlsleI/3nDFIKWk7EoSYFGZHEoSLkBsVGUYfhMUAJ8pgmgqmsBhljgQmoymqBGv5y6ukd9mwmo3mXbPebpV1VNEpOkMXyEJXqI1uUAd1EUGP6Bm9ojftSXvR3rWPxWhFK3eO0R9onz/3tJax</latexit>- Manipulation intensity
the fraction of price deviation;
- Transaction risk
# transactions / # arrivals
D0
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<latexit sha1_base64="Yr1pBXtGQ0+Rtn2nqEmST9IduXY=">AB6nicbVBNS8NAEJ3Ur1q/qh69LBbBU0mkoMeiBz1WtB/QhrLZTtqlm03Y3Qgl9Cd48aCIV3+RN/+N2zYHbX0w8Hhvhpl5QSK4Nq7RTW1jc2t4rbpZ3dvf2D8uFRS8epYthksYhVJ6AaBZfYNwI7CQKaRQIbAfjm5nfkKleSwfzSRBP6JDyUPOqLHSw23f65crbtWdg6wSLycVyNHol796g5ilEUrDBNW67mJ8TOqDGcCp6VeqjGhbEyH2LVU0gi1n81PnZIzqwxIGCtb0pC5+nsio5HWkyiwnRE1I73szcT/vG5qwis/4zJDUq2WBSmgpiYzP4mA6QGTGxhDLF7a2EjaizNh0SjYEb/nlVdK6qHq1au2+Vqlf53EU4QRO4Rw8uIQ63EDmsBgCM/wCm+OcF6cd+dj0Vpw8plj+APn8wfDQY12</latexit>- Adapt SP to evade detection while preserving manipulation effects
An Adversarial Learning Framework to Evade Detection
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- A recursive training procedure
Empirical Evaluation
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- Similarity to market making;
- Preservation of manipulation effects.
Similarity to Market Making
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Ø Quote simultaneously on both sides of the market; Ø Place large orders behind smaller ones.
SP SP1 SP SP2 SP SP3 SP SP
SP1 → SP2 → SP3 →
- Closer resemblance to MM
- Orders cover a wider range of prices with small quantities
- Buy and sell orders are better balanced
- Degraded spoofing effect
- reduced manipulation intensity
- higher transaction risk
Combine Agent-Based Simulation and Adversarial Learning to Detect Market Manipulation
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Generate New Manipulation Patterns Verify the Manipulation Effects
Recap: GANs for Financial Modeling
- Train model to generate realistic order streams
- An adversarial learning framework for market manipulation
- Reason about how a manipulator might mask its behavior
- Understand the dynamics of evasion and detection
- Generate a diverse set of manipulative patterns to improve detection
robustness
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