Yahoo just wrote down another $482 million from Tumblr, the company it bought for $1 billion

Yahoo just announced that it wrote down $482 million in impairment costs from Tumblr, the social media site it bought for $1.1 billion in 2013.

That's the second time Yahoo wrote off Tumblr's value this year. In February, it disclosed its first non-cash impairment charge that cost $230 million.

Yahoo broke down the latest Tumblr write downs in two buckets:

• $395 million in "goodwill" impairment charges
• $87 million in "intangible impairment" charges

Yahoo said the charges were due to a combination of factors "including decreases in our projected Tumblr operating results and estimated future cash flows."

Given Yahoo said that the goodwill portion of the Tumblr deal was $750 million at the time of the purchase, today's write down means Yahoo's lost over 80% of the price it overpaid for Tumblr.

Granted, write-offs are non-cash charges, meaning Yahoo won't lose any cash over the impairment charges. But it's still a huge blow to the balance sheet, and another dark spot to Yahoo CEO Marissa Mayer's acquisition strategy, which heavily touted Tumblr's acquisition as one of its most important deals.

In fact, Yahoo may have already saw this coming months ahead of today's announcement. In a February filing, Yahoo warned that there's a chance that the company might write off the entire value of Tumblr's goodwill value.