A weak form of market efficiency implies that:

A) investors would be able to earn abnormal returns by using publicly available information.
B) a security's price at a particular time fully reflects the information contained in its sequence of past prices.
C) investors would be unable to earn abnormal returns by trading on private information.
D) a security's price at a particular time fully reflects both publicly and privately available information.

Market Efficiency

The concept that all available information is fully reflected in securities' prices, making it impossible to consistently achieve higher returns without taking on additional risk.

Abnormal Returns

Returns on a security that exceed what is predicted by market models, often attributed to unforeseen events or information.

Publicly Available Information

Information that is accessible to the general public, including but not limited to financial reports, press releases, and government documents.