July 31 (Reuters) - Roblox shares plunged nearly 30% on Friday, set for their worst one-day decline on record, after the gaming ‌platform forecast a sharp drop in bookings, stocking concerns that recommendation ‌algorithm changes could further pressure near-term spending. If losses hold, Roblox is on track to erase ​more than $10 billion from its market value, which stood at about $34.9 billion before the selloff. • Roblox said on Thursday it revamped its recommendation algorithm to prioritize games with stronger long-term retention over "cash-grabby" titles focused on short-term spending, hurting ‌bookings as users shifted ⁠toward less-monetized experiences. • The changes led second-quarter bookings to the low end of Roblox's forecast range at $1.56 billion, with ⁠executives cautioning that monetization weakness could persist in the current quarter. • Roblox forecast its first quarterly bookings decline in four years, expecting a 14% to 18% year-over-year drop in the third quarter, compared with LSEG-compiled estimates for roughly an 8% decline.