Born This Way: It was intended to be the album of the decade, but sadly didn't even achieve album of the year. It was overshadowed and other than the title track and The Edge Of Glory, the expectations weren't reached in the singles department. She had her first chart entry that didn't hit top 10. While 6 million is good, it's nothing like The Fame/The Fame Monster level of size. The era was supposed to grow, but it shrunk, and it shrunk by a lot. It had a massive amount of promo and while it had a huge opening of 2 million, that was a third of its entire sales.
Talk That Talk: With We Found Love completely on everyone's minds, everyone was expecting big things from the album. Most people thought it'd replicate the success of Loud. You Da One was released and became at top 20 hit thanks to a radio deal, but dropped like a rock afterwards. The album obviously didn't hit #1 and the first-week sales were lower than Loud's on Black Friday week. While chances are it'll hit platinum in a few months, it hasn't after over 5 months. Where Have You Been hasn't taken its course yet, which is probably going to be pretty damn successful, but I can't see it helping her get past 3.5 million or so. Its too early to say where sales will end.
Femme Fatale: Hold It Against Me and Till The World Ends were both huge and I Wanna Go was a hit as well. Britney Spears has one of the most loyal followings in the music industry. However, a year later after the tour and singles it hasn't even pushed 900k. Sure, it didn't get a ton of promotion (can only think of TTWE at the BBMAs and the GMA show), but after a whole era it hasn't even gotten 900k sales. Especially since it's the Princess of Pop, these sales are very disappointing. Not even mentioning the worldwide sales, cause those are quite upsetting as well.
4: After the huge era that was I Am... Sasha Fierce, everyone was excited for the world's Most Universally Loved Superstar to have a great album. And she did. The album itself got good reviews and the singles were good. The problem? It underperformed worldwide after a huge chunk of promotion, and nearly 10 months later it hasn't scanned more than 2.5 million worldwide. While she is more directed towards the US, it's hard to say that 2.5 is lackluster considering IASF got around 7 million (not only that, but the singles were memorable). While End Of Time could save it from its very lackluster performance, 4 seems like it'll be stuck under 3 million sales worldwide.
Overall, I say Femme Fatale was the most disappointing in sales. I mean, damn.
