Evaluate whether the following actions are likely to increase stock market efficiency, decrease it, or leave it unchanged, and explain why.

a. The government imposes a transaction tax of 1% on all stock transactions.

Increase efficiency ____ Decrease efficiency ____ Leave unchanged ____

b. The securities exchange regulators impose a restriction on all short sales to prevent rampant speculation.

Increase efficiency ____ Decrease efficiency ____ Leave unchanged ____

c. An options market, trading call and put options, is opened up, with options traded on many of the stocks listed on the exchange.

Increase efficiency ____ Decrease efficiency ____ Leave unchanged ____

d. The stock market removes all restrictions on foreign investors acquiring and holding stock in companies.

Increase efficiency ____ Decrease efficiency ____ Leave unchanged ____