Q2. What have the authors stated for future works in "Département des sciences économiques de l'université catholique de louvain commonalities in the order book" ?
Secondly, in a cross section framework, the authors run regressions where the stock specific explanatory powers of the shift and rotation factor are regressed on a stock specific measure of the informational content of the order flow and a transaction costs measure that is purged of informational effects.
Q3. What is the effect of a properly constructed order imbalance indicator?
If the rotation factor qualifies as a liquidity factor then the authors would expect a positive effect of a properly constructed order imbalance indicator.
Q4. How many principal components are needed in the visible-hidden PCA?
Whilst in the latter application two principal components (identified as shift and rotation factor) achieved a cumulative R2 of about 0.92, the cumulative explanatory power of the first two principal components in the joint visible-hidden PCA is only .77 (average across stocks).
Q5. What is the importance of the disequilibrium between buyers and sellers?
19Seppi (1997) stresses the importance of the disequilibrium between buyers and sellers in that a larger proportion of buy than sell trades increase the likelihood of execution for sell limit orders.
Q6. What is the first application of PCA to order book data?
Since PCA requires standardized stationary data input (otherwise the variables with largest sample variance tend to receive too much weight) 8Gouriéroux, Le Fol, and Meyer (1998) present the first application of PCA to order book data of French Euronext-traded stocks.
Q7. What is the empirical application of Xetra?
The empirical application deals with the Xetra trading system, which is a pure automated auction market similar to Euronext or the Hong Kong stock exchange.
Q8. What is the explanatory power of the first n principal components?
The explanatory power (referred to as cumulative R2) of the first n principal components F1, F2, . . . , Fn can be computed by dividing the sum of the n first eigenvalues by the total sum of all N eigenvalues.
Q9. What are the regressors of the shift and rotation factors?
For this purpose the authors estimate regressions where the extracted shift and rotation factors serve as dependent variables and indicators suggested by microstructure theory as regressors.
Q10. What is the unit price at(v) of a buy of size v at time?
The available pre-trade liquidity of the book can be characterized by the unit price for selling v shares at time t:bt(v) = ∑k bk,tvk,t v(1)where v is the volume executed at k different unique bid prices bk,t with corresponding volumes vk,t standing in the limit order book at time t. The unit price at(v) of a buy of size v at time t can be computed analogously.