I am writing to formally report a critical and persistent issue regarding historical and daily data updates across multiple markets—not only for Borsa Istanbul (BIST - .IS), but also periodically for US equities across NASDAQ, S&P 500, and Dow Jones.

Currently, daily end-of-day data for these tickers frequently suffers from severe delays (up to 18 hours) or fails to populate entirely via the Yahoo Finance API and web downloads. This intermittent data gap directly disrupts automated workflows and technical analysis that require reliable end-of-day bar updates.

Since these are major global exchanges, having dependable and timely historical daily data is crucial. Please escalate this widespread data feed issue to your data engineering team so the sync process can be properly stabilized.

Looking forward to a resolution on this matter.