Flexible Share Repurchase Methods

XYZ Corporation is considering different methods for repurchasing shares as part of its capital management strategy. The management is particularly interested in understanding the implications of each method on the company's financials and shareholder perception. Management has identified three common methods of share repurchase: open market purchases, tender offers, and direct negotiation with major shareholders.

Each method has distinct characteristics and could potentially affect the company's stock price, investor sentiment, and financial metrics in various ways.

Based on this context, which of the following methods of share repurchase is generally considered the most flexible in terms of execution and can be conducted over time without the obligation to buy a set number of shares?