Primary Characteristic of a Company's Legal Personality:
The primary characteristic of a company's legal personality is that it has perpetual existence regardless of changes in membership. This means that the company exists as a separate legal entity distinct from its owners or shareholders.

Explanation:
1. Legal Personality:
A company is considered a separate legal entity from its owners or shareholders. This means that it has its own legal rights and obligations, and can enter into contracts, sue or be sued, and own property in its own name. This legal personality allows the company to operate independently and have a continuous existence.

2. Perpetual Existence:
One of the key characteristics of a company's legal personality is its perpetual existence. Unlike a sole proprietorship or a partnership, which may cease to exist upon the death or withdrawal of the owner(s) or partner(s), a company continues to exist even if there are changes in its ownership or membership. This perpetual existence is ensured through the process of incorporation, which grants the company a separate legal status.

3. Continuity and Stability:
The perpetual existence of a company provides several advantages. Firstly, it ensures continuity and stability in the business operations of the company. Even if one or more shareholders decide to sell their shares or leave the company, the company can continue to operate without any interruption. This is particularly beneficial in the case of large corporations where ownership changes frequently.

4. Limited Liability:
Another significant advantage of a company's legal personality is the concept of limited liability. Shareholders are generally not personally liable for the company's debts and obligations beyond the amount they have invested in the company. This limited liability protection encourages investment and allows shareholders to take risks without risking their personal assets.

5. Transferability of Shares:
The perpetual existence of a company also facilitates the transferability of shares. Shareholders can freely buy and sell their shares in the company without affecting the company's existence. This provides liquidity to the shareholders and allows for the easy transfer of ownership.

Conclusion:
The primary characteristic of a company's legal personality is its perpetual existence. This allows the company to operate independently, have continuity and stability, provide limited liability to shareholders, and facilitate the transferability of shares. These advantages make the concept of a separate legal entity essential for the functioning and success of a company.