Ok, so there are the five core Funds that TSP has.
The G, F, C, S, and I Funds. If you don't know what those are, I can go more in depth later.
The L Funds are retirement lifecycle funds, with the number indicating the kind of investor that should likely use that particular L Fund. For example, if someone will likely retire in the early 2050s, then he should probably use the L2050 or L2055 Fund. Linc means "L Income", which is intended for retirees.
The L Funds are designed as a "set it and forget it" approach. They are made up of various quantities of the core Funds (G, F, C, S, and I). To compare:
L2070's makeup is 0.36% G, 0.64% F, 51.48% C, 12.87% S, and 34.65% I
L2030's makeup is 34% G, 6% F, 31% C, 8 % S, and 21% I.
LIncome's makeup is 68.22% G, 5.53% F, 13.67% C, 3.39% S, and 9.19% I.
As you can see, the further out a L Fund's target retirement date is, the more aggressive it is. As the retirement date gets closer, it automatically starts shifting more and more conservative. L Income's makeup is pretty static, and hardly ever changes.
The L Funds are meant to have diversification for buy-and-holders in an easy, no-frills approach. However, some feel that the allocations are too conservative, use too much of the I Fund, and will cause the investor to miss out on gains because of how much money is kept in bonds (G & F Funds) and the international market (I Fund).
Hope that helps! Let us know if there's any other questions. Glad to be of assistance.
Thanks for that breakdown! I do know what the G,F,C,S & I funds are. I am in the middle of reading your seasonal musings posts. Thank you for taking the time to explain the strategy!!! Super easy read and I even laughed a couple times so far lol I am very interested in the taking the seasonal approach. Can you (or can you direct me to the forum members who could) pass down your Excel Workbook?
That workbook hasn't been updated in a couple of years. A better option is to go over to TSPCalc.com, where not only is everything I've done replicated there, but with a ton more options as well.