Why have Telstra shares lost 16% since May?

Since mid-May, the S&P/ASX 200 Index (ASX: XJO) has held up relatively well. Despite some volatility along the way, the ASX 200 presently sits about 2% above where it was back on 19 May. However, we cannot say the same for Telstra Group Ltd (ASX: TLS) shares.

Back in May,…